" At the Lote Tree the Prophet received for his people the command of fifty prayers a day...They made their descent through the seven Heavens even as they had ascended. The Prophet said: “On my return, when I passed Moses - and what a good friend he was unto you! - he asked me: ‘How many prayers have been laid upon thee?’ I told him fifty prayers every day and he said: ‘The congregational prayer is a weighty thing, and thy people are weak. Return unto thy Lord, and ask Him to lighten the load for thee and thy people.’ So I returned and asked my Lord to make it lighter, and He took away ten. Then I passed Moses again, and he repeated what he had said before, so I returned again, and ten more prayers were taken from me. But every time I returned unto Moses he sent me back until finally all the prayers had been taken from me except five for each day and night. Then I returned unto Moses, but still he said the same as before; and I said: ‘I have returned unto my Lord and asked Him until I am ashamed. I will not go again.’ And so it is that he who performeth the five in good faith and in trust of God’s bounty, unto him shall be given the meed of fifty prayers. "

― , Muhammad: His Life Based on the Earliest Sources