Bukhari :: Book 1 :: Volume 2 :: Hadith 54

Narrated Jarir bin Abdullah:

I gave the pledge of allegiance to Allah's Apostle for the following:

1. offer prayers perfectly

2. pay the Zakat (obligatory charity)

3. and be sincere and true to every Muslim.

Source materials are from the University of Southern California MSA site
Hadith eBooks converted from Imaan Star