General Behavior (Kitab Al-Adab)
Dawud :: Book 41 : Hadith 4978
Narrated Abdullah ibn AbulHamsa':
I bought something from the Prophet (peace_be_upon_him) before he received his Prophetic commission, and as there was something still due to him I promised him that I would bring it to him at his place, but I forgot. When I remembered three days later, I went to that place and found him there. He said: You have vexed me, young man. I have been here for three days waiting for you.