Sahih Bukhari
Good Manners and Form (Al-Adab)
Volume: 008 / Book Number: 073 / Hadith Number: 123
Narrated 'Aisha:
The Prophet did something and allowed his people to do it, but some people refrained from doing it. When the Prophet learned of that, he delivered a sermon, and after having sent Praises to Allah, he said, "What is wrong with such people as refrain from doing a thing that I do? By Allah, I know Allah better than they, and I am more afraid of Him than they."