Sahih Bukhari
Sahih Bukhari Volume 009, Book 089, Hadith Number 309.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 89. Judgments (Ahkaam)
Narrated By 'Abdullah bin 'Umar : Whenever we gave the Pledge of allegiance to Allah's Apostle for to listen to and obey, he used to say to us, for as much as you can."