Sahih Muslim , Book 4, Hadith 2067 (USC-MSA) ⓘ
Abu Huraira reported Allah's Messenger as saying: He who offers prayer for the dead, for him is (the reward of) one qirat; and he who follows the bier till it is placed in the grave, for him (is the reward of) two qirats. I (Abu Hazim, one of the narrators) said: Abu Huraira, what is a qirat? He said: It is like the hill of Uhud.
حَدَّثَنِي مُحَمَّدُ بْنُ حَاتِمٍ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ يَزِيدَ بْنِ كَيْسَانَ، حَدَّثَنِي أَبُو حَازِمٍ عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَنْ صَلَّى عَلَى جَنَازَةٍ فَلَهُ قِيرَاطٌ وَمَنِ اتَّبَعَهَا حَتَّى تُوضَعَ فِي الْقَبْرِ فَقِيرَاطَانِ " . قَالَ قُلْتُ يَا أَبَا هُرَيْرَةَ وَمَا الْقِيرَاطُ قَالَ " مِثْلُ أُحُدٍ " .
also referenced under: Book 11, Hadith 72 (In-Book) & Hadith 945 (Reference)