Kitāb al-Muʾmin
Hadith 168168 - وعن أبي عبد الله عليه السلام قال: أول ما يتحف به المؤمن في قبره أن يغفر لمن تبع جنازته.
168. It has been reported that Abu 'Abd Allah (a.s) said: The first gift that a believer is presented with in his grave is the forgiveness for those who accompanied his bier.