Anas bin Malik narrated:
“On the Night of Isra, fifty prayers were made obligatory upon the Prophet (peace be upon him). Then it was decreased until it was made five. Then it was called out: ‘O Muhammad! Indeed My Word does not change; these five prayers will be recorded for you as fifty.'”
Jami` at-Tirmidhi, Vol. 1, Book 2, Hadith 65
