Jami` at-Tirmidhi Book 10, Hadith 77
"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."
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 Messenger of Allah said: "Whenever you see a funeral (procession), stand up until it goes ahead of you or it is put down."