Those who said: His Islam is judged valid

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that a Jewish boy used to serve the Prophet (peace and blessings be upon him). He fell ill, so the Prophet (peace and blessings be upon him) went to visit him. The Messenger of Allah (peace and blessings be upon him) sat by his head. The boy looked at his father, and he said: "Obey Abu al-Qasim." So he became Muslim. When the Messenger of Allah (peace and blessings be upon him) came out, he was saying: "All praise is for Allah who has saved him from the Fire through me."

Abu Hamzah, a man of the Ansar, heard Sayyiduna Zayd bin Arqam (may Allah be pleased with him) say that the first person to pray with the Prophet (peace and blessings be upon him) was Sayyiduna Ali bin Abi Talib (may Allah be pleased with him). He said: I mentioned that to Ibrahim (may Allah have mercy on him), and he rejected it and said: It was Sayyiduna Abu Bakr (may Allah be pleased with him).

Al-Najib bin al-Sari (may Allah have mercy on him) said: Sayyiduna Ali (may Allah be pleased with him) said: I preceded them to Islam while I was a boy who had not yet reached puberty.
This saying is widespread among people as a saying of Ali (may Allah be pleased with him), but it has not reached us with a chain of the kind that can be used as evidence.
The people of knowledge differed over the age of Sayyiduna Ali (may Allah be pleased with him) when he accepted Islam.

It is narrated from Urwah (may Allah have mercy on him) that when Sayyiduna Ali (may Allah be pleased with him) accepted Islam, he was eight years old.

Muhammad bin Ishaq said: When Sayyiduna Ali (may Allah be pleased with him) accepted Islam, he was ten years old.

It is narrated from Mujahid that when Sayyiduna Ali (may Allah be pleased with him) accepted Islam, he was ten years old.

Al-Husayn bin al-Walid (may Allah have mercy on him) said: I heard Sharik (may Allah have mercy on him) say that Sayyiduna Ali (may Allah be pleased with him) became Muslim at the age of eleven.

It is narrated from al-Hasan (may Allah have mercy on him) that the first to accept Islam was Ali bin Abi Talib (may Allah be pleased with him), and he was fifteen or sixteen years old.
Another narration has the words: The first to accept Islam after Khadijah (may Allah be pleased with her) was Ali (may Allah be pleased with him), and he was fifteen or sixteen years old at the time.

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) gave the banner to Sayyiduna Ali (may Allah be pleased with him) on the day of Badr, when he was twenty years old.
Imam Ahmad (may Allah have mercy on him) said: The Battle of Badr took place a year and a half after the Messenger of Allah (peace and blessings be upon him) came to Madinah. They differed over how long he stayed in Makkah after he was sent as a prophet: it is said ten years, it is said thirteen years, and it is said fifteen years. If it was ten, and it is correct that Sayyiduna Ali (may Allah be pleased with him) was twenty on the day of Badr, then his age when he accepted Islam comes close to what Urwah said. If it was thirteen or fifteen years, then his age was less than that.
They also differed over the age of Sayyiduna Ali (may Allah be pleased with him) at the time of his martyrdom: it is said sixty-five years, it is said sixty-three years, and less than that has also been said; the best known is sixty-three, at the end of forty years from the emigration of the Messenger of Allah (peace and blessings be upon him). So his age when he accepted Islam comes to thirteen years on the view of those who say the Messenger of Allah (peace and blessings be upon him) stayed in Makkah ten years, and to ten years on the view of those who say thirteen. Thus in most reports, when he (may Allah be pleased with him) prayed with the Prophet (peace and blessings be upon him), he had reached an age at which it is possible that he had attained puberty. The verses of poetry that are narrated are open to interpretation, besides their chain being weak. Moreover, the ruling that only the statement of one who has reached puberty is valid, and not that of a discerning child, was legislated after Sayyiduna Ali (may Allah be pleased with him) accepted Islam, so his Islam was judged valid: either because he lived on until he professed Islam after reaching puberty, or because the Prophet (peace and blessings be upon him) addressed him with the call to Islam while other boys were not addressed, or because at that time the statement of a discerning child was judged valid before the Shari'ah came with something else, or because he had already had a wet dream and so had reached puberty. And Allah knows best.
In the narration of Qatadah, al-Hasan al-Basri and others held that when Sayyiduna Ali (may Allah be pleased with him) accepted Islam he was fifteen or sixteen years old.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) stayed in Makkah for fifteen years: for seven years he heard the voice and saw the light but saw nothing (else), and for eight years revelation came to him; and he (peace and blessings be upon him) stayed in Madinah for ten years.
In the narration of Hajjaj bin Minhal: For seven years he saw the light and heard the voice, and for eight years revelation came to him, and he (peace and blessings be upon him) stayed in Madinah for ten years.
Imam Ahmad (may Allah have mercy on him) said: Al-Hasan held a similar view regarding how long revelation came to the Prophet (peace and blessings be upon him) in Makkah. On this breakdown, the Islam of Sayyiduna Ali (may Allah be pleased with him) came after those seven years, that is, after revelation came to the Prophet (peace and blessings be upon him), so his stay in Makkah after revelation was eight years. Then, on the view of those who say that Sayyiduna Ali (may Allah be pleased with him) was martyred at sixty-three, at the end of forty years from the emigration of the Messenger of Allah (peace and blessings be upon him), he was fifteen years old when he became Muslim, as we have narrated from al-Hasan al-Basri (may Allah have mercy on him). However, the well-known reports about the Prophet's (peace and blessings be upon him) stay in Makkah after revelation indicate more than that. And Allah knows best.

It is narrated from Sayyiduna Ibn Abbas and Sayyidah Aishah (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) stayed in Makkah for ten years with the Qur'an being revealed to him, and in Madinah too, for ten years, the Qur'an was revealed to him (peace and blessings be upon him).

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) stayed in Makkah for thirteen years and in Madinah for ten years, and when he passed away he was sixty-three years old.

It is narrated from Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) stayed in Makkah for thirteen years, and when he passed away he was sixty-three years old.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) was given prophethood at the age of forty. He (peace and blessings be upon him) stayed in Makkah for thirteen years, with revelation coming to him. Then he was commanded to emigrate. He (peace and blessings be upon him) spent ten years in emigration, and when he passed away he was sixty-three years old.

It is narrated from Urwah (may Allah have mercy on him) that when Sayyiduna al-Zubayr (may Allah be pleased with him) accepted Islam, he was eight years old.