Sahih Bukhari
Accepting Information Given by a Truthful Person
Volume: 009 / Book Number: 091 / Hadith Number: 355
Narrated 'Abdullah:
The Prophet led us in Zuhr prayer and prayer five Rakat. Somebody asked him whether the prayer had been increased." He (the Prophet ) said, "And what is that?" They (the people) replied, "You have prayed five Rakat." Then the Prophet offered two prostrations (of Sahu) after he had finished his prayer with the Taslim.