ibn Umar · Combing the Hair (Kitab Al-Tarajjul)

That he heard Mu'awiyah b. Abi Sufyan say during the Hajj when he was on the pulpit and took a lock of hair which was in the hand of the guard, saying: O people of Medina, where are your scholars ? I heard the Messenger of Allah (ﷺ) forbidding such a think as this and said: The children of Isra'il perished when their women practised it.

The Prophet (ﷺ) gave the children of Ja'far three day' time to visit them. He then came to visit them, and said: Do not weep over my brother after this day. He said: Call to me the children of my brother. We were brought to him as if we were chicken. He said: Call a barber to me. He then ordered and our heads were shaved.

The Messenger of Allah (ﷺ) forbade qaza'. Qaza' means having part of a boy's head shaved and leaving part unshaven.

the Prophet (ﷺ) forbade qaza' which means that the head of a boy is shaved and a lock is left.

He did not dye his hair, but Abu Bakr and 'Umar dyed their hair.