Sahih Bukhari
Call to Prayers (Adhaan)
Volume: 001 / Book Number: 011 / Hadith Number: 611
Narrated 'Abdullah bin Abi:
Qatada, My father said, "Allah's Apostle said, 'If the Iqama is pronounced, then do not stand for the prayer till you see me (in front of you) and do it calmly.' "