Bulugh al-Maram, Book 3, Hadith 591 (English) ⓘ
Abu Hurairah (RAA) narrated that the Messenger of Allah said: “If you offer the funeral prayer for a deceased person, supplicate Allah sincerely for him." Related by Abu Dawud.
وَعَنْهُ أَنَّ اَلنَّبِيَّ - صلى الله عليه وسلم -قَالَ: { إِذَا صَلَّيْتُمْ عَلَى اَلْمَيِّتِ فَأَخْلِصُوا لَهُ اَلدُّعَاءَ } رَوَاهُ أَبُو دَاوُدَ, وَصَحَّحَهُ ابْنُ حِبَّانَ 1. 1 - حسن. رواه أبو داود (3199)، وابن حبان (3076).
also referenced under: Book 3, Hadith 35 (In-Book)