Sahih Bukhari Volume 6, Book 60, Hadith Number 191.

Narrated By Shaqiq : Abu Mas’ud Al-Ansari said, “Allah’s Apostle, used to order us to give alms. So one of us would exert himself to earn one Mud (special measure of wheat or dates, etc.,) to give in charity; while today one of us may have one hundred thousand.” Shaqiq said: As if Abu Masud referred to himself.