Short answer
Yes. The Qur'an calls Muhammad (ﷺ) "the Seal of the Prophets" (33:40). In Arabic, a seal is the stamp that closes a letter, and the same word means the last of a company. The Prophet (ﷺ) explained it himself. He said he was the missing brick that completes a house, and that the prophets were sealed with him. The Arabic dictionaries and the first commentators on the Qur'an say the same. Ahmadi readers love the Prophet (ﷺ) and honour this verse. Some read "seal" as a mark of approval, so that prophets could still come under his seal. The Arabic and his own words do not allow that. Muslims also hold that believing him to be the last prophet is part of what the testimony of faith affirms. So accepting a prophet after him contradicts it.
Full explanation
What the verse says
The verse answers a question about adoption. Muhammad (ﷺ) was not the father of Zayd, whom he had raised as a son. It ends by naming him the Messenger of Allah (﷾) and khatam al-nabiyyin, the Seal of the Prophets. Ibn Kathir, a 14th-century commentator, calls the verse explicit: there is no prophet after him. If there is no prophet, he adds, there is no messenger either, since every messenger is a prophet.
“Muhammad is not the father of any of your men, but (he is) the Messenger of Allah, and the Seal of the Prophets: and Allah has full knowledge of all things.”
Ibn Kathir explains that the verse forbids calling Zayd "son of Muhammad", since the Prophet (ﷺ) was not the father of any of the men. On "the Seal of the Prophets" he says the verse is explicit that there is no prophet after him. If there is no prophet after him, there is no messenger either, since every messenger is a prophet and not the other way round. He adds that the reports of this are mutawatir, from a group of Companions, and gives the hadith of the missing brick and the hadith of Anas.
What khatam means in Arabic
Khatam means a seal or signet, the stamp pressed on a letter. The old dictionaries also give a second meaning: the last part of a thing. Lane's Arabic-English Lexicon lists "the last of a company of men" and names this verse as its example, "the last of the prophets". Ibn Manzur's Lisan al-Arab (d. 1311) says the khatam of a people is their last, and that the verse means "the last of them". Al-Jawhari's dictionary (d. about 1003) gives "the last of a thing" and, in the next breath, calls Muhammad (ﷺ) the khatam of the prophets. The Qur'an uses the root this way too. In 83:26 the "seal" of the drink is musk, the last thing the drinkers taste. In 2:7 Allah (﷾) sets a "seal" on hearts, so that nothing enters or leaves them.
Gathers the classical Arabic dictionaries. Under kh-t-m, khatam is first a signet or seal, a ring used for sealing. The entry then gives, as a figurative sense, the end or last part of a thing, and the last of a company of men. It names Qur'an 33:40, khatam al-nabiyyin, with the gloss "the last of the prophets". Under 83:26 it explains khitam as the last thing the drinkers perceive, the scent of musk. The ornament it mentions is the ring on the finger. The entry gives no sense of "the best".
Ibn Manzur gathers the older dictionaries. The khatim of a thing and its khatima are its end and last part, and the khitam of a drink is its last. The khitam, khatim and khatam of a people are their last, from the early philologist al-Lihyani. The Prophet (ﷺ) is the khatim of the prophets, and the verse "the Seal of the Prophets" means "the last of them", from al-Azhari. One of his names is al-'Aqib, and its meaning is the last of the prophets. The khatm on a heart means that nothing enters it and nothing leaves it.
Al-Jawhari gives khatimat al-shay' as "the last of a thing", and says Muhammad (ﷺ) is the khatim of the prophets. He explains khitamuhu misk (83:26) as "its last", because the last thing the drinkers find is the scent of musk. He also gives khatamtu al-Qur'an as "I reached its end".
“The seal thereof will be Musk: And for this let those aspire, who have aspirations:”
“Allah hath set a seal on their hearts and on their hearing, and on their eyes is a veil; great is the penalty they (incur).”
The Prophet (ﷺ) used the same word himself
He compared the prophets to a man who built a fine house but left one brick missing. He said he was that brick, and that he was the Seal of the Prophets. In another report he said: I came and sealed the prophets. In a third he said the prophets were sealed with him. All three use the root khatama, and all place him at the end of the line. He also said: I am the last of the prophets. There he used akhir, the plain Arabic word for "last". He named himself al-'Aqib, too, "the last to come". The early narrator al-Zuhri explained it as the one after whom there is no prophet.
Abu Hurayra reports that the Prophet (ﷺ) compared himself and the prophets before him to a man who built a fine house but left the place of one brick empty in a corner. People walked round it, admired it, and wished the brick were in place. He said: I am that brick, and I am the Seal of the Prophets (khatim al-nabiyyin).
Abu Hurayra reports that the Prophet (ﷺ) likened himself and the prophets before him to a man who built a fine house and left one brick missing. People walked round it, wished the brick were in place, and he said he was that brick. In the third version he adds: and I am the Seal of the Prophets (khatam al-nabiyyin).
Jabir reports that the Prophet (ﷺ) likened himself and the prophets to a man who built a house and finished it, except for the place of one brick. He said: I am the place of that brick; I came and sealed the prophets (fa-khatamtu al-anbiya').
Abu Hurayra reports that the Prophet (ﷺ) named six things in which he was favoured above the other prophets. Among them: he was sent to all creation, and the prophets were sealed with him (khutima biya al-nabiyyun).
Abu Hurayra says that prayer in the Prophet's (ﷺ) mosque is better than a thousand prayers in other mosques except the Sacred Mosque, and the narrator Abdullah ibn Ibrahim ibn Qariz testifies that he heard Abu Hurayra say that the Prophet (ﷺ) said: for I am the last of the prophets (akhir al-anbiya') and my mosque is the last of the mosques.
Jubayr ibn Mut'im reports that the Prophet (ﷺ) named himself Muhammad and Ahmad, al-Mahi (by whom unbelief is wiped out), al-Hashir (at whose feet people are gathered) and al-'Aqib. The report adds that al-'Aqib is the one after whom there is no prophet. In 2354c the early narrator al-Zuhri, asked what al-'Aqib means, gives the same answer.
How the first Muslims understood it
Al-Tabari, an early commentator (d. 923), explains the verse this way. Allah (﷾) sealed prophethood and stamped it. It is not opened for anyone after him until the Hour. He reports Qatada, a scholar of the generation after the Companions, saying it means the last of them. Al-Qurtubi notes that the verse is read khatam (the seal) or khatim (the one who seals). Either way, the prophets were closed by him. Ibn Abi Awfa, a Companion, was asked about the Prophet's (ﷺ) infant son Ibrahim. He said that had a prophet been due after Muhammad (ﷺ), the boy would have lived. But there is no prophet after him.
Al-Tabari explains "the Seal of the Prophets" as the one who sealed prophethood and stamped it, so that it is not opened for anyone after him until the Hour. He reports Qatada: "the Seal of the Prophets" means the last of them. He notes that most readers read khatim (the one who seals), while Asim and al-Hasan read khatam, which he glosses as "the last of the prophets", as in 83:26. He adds that Ibn Mas'ud is reported to have read the verse "but a prophet who sealed the prophets".
Al-Qurtubi records that Asim alone read khatam, meaning that the prophets were sealed by him, so that he is like the seal and stamp upon them. Most read khatim, meaning that he sealed them, and came last of them. He quotes Ibn Atiyya: the scholars of the community, earlier and later, take these words in full generality, as a text that there is no prophet after him. He also gives Muslim's reports of the brick hadith, including "I came and sealed the prophets".
Isma'il ibn Abi Khalid asked the Companion Abdullah ibn Abi Awfa whether he had seen Ibrahim, the Prophet's (ﷺ) son. He said the child died young, and that if it had been decreed that a prophet should come after Muhammad (ﷺ), his son would have lived; but there is no prophet after him.
What the Ahmadi community says the word means
Mirza Ghulam Ahmad of Qadian (1835-1908) honoured the Prophet (ﷺ) as khatam al-nabiyyin, and his community does so today. He taught that the Prophet holds the seal without whose attestation no grace reaches anyone. In his view independent prophethood ended with Muhammad (ﷺ), but a prophet who receives revelation through obeying him could still come. The community's own article on the dictionaries gives several meanings. These include "the best and most perfect of the Prophets" and, "secondarily", "the last of the Prophets". The community's WhyAhmadi site goes further. It says that in the Prophet's (ﷺ) time khatam was never used to mean last.
Mirza Ghulam Ahmad writes that Muhammad (ﷺ) became Khatamul-Anbiya' (the Seal of the Prophets) in the sense that he possesses the seal without whose attestation no grace reaches anyone. He writes that independent prophethood has ended with the Prophet, but that prophethood by way of zill (reflection), received purely through obedience to him, will last until the Day of Judgment. He also writes that for his ummah the door of converse and communion with the Divine will never be closed until the Day of Judgment.
The article on the finality of prophethood quotes the dictionaries for khatam: a seal or stamp, a signet-ring, the end or last part of a thing, and embellishment, the best and most perfect. It holds that sealing is the first sense and bringing something to an end a secondary sense. It concludes that khatam al-nabiyyin means the Seal of the Prophets, the best and most perfect of them, and, quoting the community's Five Volume Commentary, "secondarily" the last of the prophets. It lists four possible meanings, including last of the law-bearing prophets.
The community's page says that khatam primarily means a seal, and also the best and most perfect, and that in the Prophet's (ﷺ) time it was never used to mean "last". It says khatam is read with a fatha, so it means "the Seal" or "the Best" of the prophets. It gives as examples a report in Kanz al-Ummal in which the Prophet tells his uncle Abbas he is "khatam of the emigrants" as he is khatam of the prophets, and the titles khatam al-awliya for al-Shafi'i and khatam al-shu'ara for Abu al-Tayyib. It argues that if "last of the prophets" ruled out later prophets, "last of the mosques" would rule out later mosques.
Does khatam only mean "the best"?
First, the dictionaries. Lane's long entry gives "seal", "signet ring" and "last". The ornament he mentions is the ring on the finger, not a rank of excellence. He gives no sense of "the best". The Ahmadi site cites later titles, such as "seal of the saints" for al-Shafi'i. These came centuries after the verse, so they cannot fix what the verse means. Second, the Prophet's (ﷺ) own verb. When he says "I came and sealed the prophets", he is closing a line, not approving one. Third, his picture. A brick set in the last gap completes the house. It does not authorise bricks added later.
Gathers the classical Arabic dictionaries. Under kh-t-m, khatam is first a signet or seal, a ring used for sealing. The entry then gives, as a figurative sense, the end or last part of a thing, and the last of a company of men. It names Qur'an 33:40, khatam al-nabiyyin, with the gloss "the last of the prophets". Under 83:26 it explains khitam as the last thing the drinkers perceive, the scent of musk. The ornament it mentions is the ring on the finger. The entry gives no sense of "the best".
Ibn Manzur gathers the older dictionaries. The khatim of a thing and its khatima are its end and last part, and the khitam of a drink is its last. The khitam, khatim and khatam of a people are their last, from the early philologist al-Lihyani. The Prophet (ﷺ) is the khatim of the prophets, and the verse "the Seal of the Prophets" means "the last of them", from al-Azhari. One of his names is al-'Aqib, and its meaning is the last of the prophets. The khatm on a heart means that nothing enters it and nothing leaves it.
Jabir reports that the Prophet (ﷺ) likened himself and the prophets to a man who built a house and finished it, except for the place of one brick. He said: I am the place of that brick; I came and sealed the prophets (fa-khatamtu al-anbiya').
Abu Hurayra reports that the Prophet (ﷺ) compared himself and the prophets before him to a man who built a fine house but left the place of one brick empty in a corner. People walked round it, admired it, and wished the brick were in place. He said: I am that brick, and I am the Seal of the Prophets (khatim al-nabiyyin).
"The last of the mosques"
The Ahmadi site argues that if "last of the prophets" ruled out later prophets, "last of the mosques" would rule out later mosques. But the Prophet (ﷺ) said the two together. He said: I am the last of the prophets, and my mosque is the last of the mosques. He used akhir, the plain word for "last", so here the word cannot mean "the best". The pairing explains itself. His mosque is the last mosque built by a prophet, because no prophet comes after him. The mosques built since are not prophets' mosques. So the hadith supports finality. It does not weaken it.
Abu Hurayra says that prayer in the Prophet's (ﷺ) mosque is better than a thousand prayers in other mosques except the Sacred Mosque, and the narrator Abdullah ibn Ibrahim ibn Qariz testifies that he heard Abu Hurayra say that the Prophet (ﷺ) said: for I am the last of the prophets (akhir al-anbiya') and my mosque is the last of the mosques.
The community's page says that khatam primarily means a seal, and also the best and most perfect, and that in the Prophet's (ﷺ) time it was never used to mean "last". It says khatam is read with a fatha, so it means "the Seal" or "the Best" of the prophets. It gives as examples a report in Kanz al-Ummal in which the Prophet tells his uncle Abbas he is "khatam of the emigrants" as he is khatam of the prophets, and the titles khatam al-awliya for al-Shafi'i and khatam al-shu'ara for Abu al-Tayyib. It argues that if "last of the prophets" ruled out later prophets, "last of the mosques" would rule out later mosques.
Where this leaves the verse
The verse, the dictionaries, the Prophet's (ﷺ) own words and the first commentators all point one way. A seal closes. Ahmadi readers can keep every honour they give him. This verse adds one more: he is the Seal of the Prophets, and no one stands after him. Muslims hold that believing this is part of the testimony of faith. To witness that he is the Messenger of Allah (﷾) is to accept what he taught, and he taught that he is the last prophet (33:40). For that reason, accepting a prophet after him contradicts the testimony. We say this plainly, and with respect for readers who love him. The next page asks whether a prophet who brings no new law could still come.
“Muhammad is not the father of any of your men, but (he is) the Messenger of Allah, and the Seal of the Prophets: and Allah has full knowledge of all things.”
Abu Hurayra reports that the Prophet (ﷺ) said the Israelites were led by prophets, and whenever one died another took his place. But there will be no prophet after me, he said; there will be caliphs, and many of them.
Perspectives
The Ahmadi view
The Ahmadi community honours Muhammad (ﷺ) as the Seal of the Prophets. Mirza Ghulam Ahmad of Qadian taught that this means the Prophet's seal authenticates every later prophet, so that only independent, law-bearing prophethood has ended.
Khatam means a seal or "the best and most perfect". In the Prophet's (ﷺ) time, they say, it was never used to mean "last".
Rebuttal
The dictionaries do give "last". Lane and Ibn Manzur list it and name this verse. Al-Jawhari sets it beside the title of the Prophet (ﷺ). The community's own article also grants "the last of the Prophets" as a meaning.
Titles such as khatam al-awliya (for al-Shafi'i) and khatam al-shu'ara show that the word means "the best".
Rebuttal
Such titles were given centuries after the verse, so they cannot fix its meaning. Lane's entry for the word has no sense of "the best".
The Prophet (ﷺ) called his uncle Abbas the khatam of the emigrants, so khatam means "best".
Rebuttal
That report is weak, so it cannot fix the meaning of the verse. It is not in Bukhari or Muslim, and the hadith critics rejected its chains. Even as the Ahmadi site gives it, the word fits "last". After the conquest of Mecca the Prophet (ﷺ) said there was no more emigration (Bukhari 2825). The title marks the end of a line.
The seal is the Prophet's (ﷺ) attestation, so later prophets may come, but only with his seal.
Rebuttal
Even a seal of approval is the last thing pressed on a letter. A seal is pressed when the letter is finished. The Prophet (ﷺ) said he was the missing brick that completes the house, and that he came and sealed the prophets. Al-Tabari says it is not opened for anyone after him.
Being the last is no honour, so the verse must mean "the best".
Rebuttal
The verse joins two facts: he is the father of none of your men, and he is the Seal of the Prophets. The Companion Ibn Abi Awfa joined them the same way. Had a prophet been due after Muhammad (ﷺ), his son would have lived. And the Prophet (ﷺ) counted being last as an honour. Among six things in which he was favoured, he named that the prophets were sealed with him.
Aisha said: say "Seal of the Prophets", but do not say "no prophet after him".
Rebuttal
That wording is hers, not the Prophet's (ﷺ). It does not say a prophet will come, and it keeps the title Seal of the Prophets. A caution about one phrase is not a promise of a new prophet. The Prophet's (ﷺ) own words say there is no prophet after him. The one prophet he said would come down, Jesus, was sent before him.
The Prophet (ﷺ) called his mosque "the last of the mosques", and mosques are still built. So "last of the prophets" need not rule out later prophets.
Rebuttal
In the same hadith he says: I am the last of the prophets. He used akhir, the plain word for "last". His mosque is the last mosque built by a prophet, because he is the last prophet. Mosques built since are not prophets' mosques. The saying supports finality.
The Islamic perspective
"Seal of the Prophets" means the last of them. The Arabic, the Prophet's (ﷺ) own words and the first commentators agree.
The Qur'an names Muhammad (ﷺ) the Seal of the Prophets.
Arabic dictionaries give "the last of a company" as a meaning of khatam. Lane and Ibn Manzur name this verse as an example.
The Prophet (ﷺ) said he was the missing brick, and that he came and sealed the prophets. He said the prophets were sealed with him, and that he is the last of the prophets.
He named himself al-'Aqib, and al-Zuhri explained it as the one after whom there is no prophet.
Al-Tabari, Ibn Kathir and al-Qurtubi read the verse as saying there is no prophet after him.