Amr bin Murrah bin 'Abdullah عمرو بن مرة بن عبد الله بن طارق · The Book of Funerals

"When you see a funeral, stand up until it has passed you, or (the body) is placed (in the grave)."

"The Janazah of a boy and a woman were brought. The boy was placed closer to the people and the woman was placed beyond him, and the funeral prayer was offered for them. Among the people were Abu Saeed Al-Khudri, Ibn Abbas, Abu Qatadah and Abu Hurairah. I asked them about that and they said: '(It is) Sunnah."'

That the Messenger of Allah announced the death of An-Najashi to the people, and he led thme out and arranged them in rows, and said the Takbir four times.