Musannaf Ibn Abi Shaybah 11967 — The reward of one who prays

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both), Sayyiduna Abu Hurayrah (may Allah be pleased with him) and Sayyiduna Abdullah (bin Mas'ud) said: Whoever offers the funeral prayer over a deceased person has one qirat (of reward), and whoever stays with it until the burial has two qirats (of reward), and a qirat is equal to Mount Uhud.