Jami` at-Tirmidhi Book 10, Hadith 76
The Messenger of Allah said: "Whoever performs the funeral prayer then he will get a reward equal to a Qirat. Whoever follows it until it is buried then he will get a reward equal to two Qirat, one of them, or the least of them, is similar to Uhud (mountain)." This was mentioned to Ibn Umar, so he sent a message to Aishah to ask her about that, and she said: "Abu Hurairah has told the truth." So Ibn Umar said: "We have missed many Qirat."
the Prophet said: "Indeed your brother An-Najashi has died. So stand to perform Salat for him." He (Imran) said: "We stood and lined up just as the deceased is lined up for, and we prayed for him just as the deceased is prayed for."
"I accompanied Abu Hurairah for ten years, and I heard him saying: 'I heard the Messenger of Allah saying: "Whoever follows a funeral, and carries it three times, then he has fulfilled the right that is required from him."