Muwatta Malik, Book 16, Hadith 547 (In-Book)

Yahya related to me from Malik from Nafi that Abdullah ibn Umar, when he prayed over the dead, would say, "Peace be upon you" loud enough for whoever was near to him to hear.

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ إِذَا صَلَّى عَلَى الْجَنَائِزِ يُسَلِّمُ حَتَّى يُسْمِعَ مَنْ يَلِيهِ ‏.‏

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also referenced under: Book 16, Hadith 25 (USC-MSA)