Sunan Ibn Majah, Volume 2, Book 6, Hadith 1462 (DarusSalam) ⓘ
It was narrated from ‘Ali that the Messenger of Allah said: “Whoever washes a deceased person, shrouds him, embalms him, carries him and offers the funeral prayer for him, and does not disclose what he has seen, he will emerge from his sins as on the day his mother bore him.”
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ الْمُحَارِبِيُّ، حَدَّثَنَا عَبَّادُ بْنُ كَثِيرٍ، عَنْ عَمْرِو بْنِ خَالِدٍ، عَنْ حَبِيبِ بْنِ أَبِي ثَابِتٍ، عَنْ عَاصِمِ بْنِ ضَمْرَةَ، عَنْ عَلِيٍّ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ غَسَّلَ مَيِّتًا وَكَفَّنَهُ وَحَنَّطَهُ وَحَمَلَهُ وَصَلَّى عَلَيْهِ وَلَمْ يُفْشِ عَلَيْهِ مَا رَأَى خَرَجَ مِنْ خَطِيئَتِهِ مِثْلَ يَوْمِ وَلَدَتْهُ أُمُّهُ " .
also referenced under: Hadith 1462 (Reference) & Book 6, Hadith 1529 (In-Book)