مُوَطَّأُ مَالِكٍ
Muwatta Malik 547
Burials
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ إِذَا صَلَّى عَلَى الْجَنَائِزِ يُسَلِّمُ حَتَّى يُسْمِعَ مَنْ يَلِيهِ .
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.
Arabic/English book reference: Book 16, Hadith 25