سنن النسائي

It was narrated that 'Amr bin 'Abasah said: "I came to the Messenger of Allah, who became Muslim with you?' He said: 'Free men and slaves.' I said: 'Is there any moment which brings one closer to Allah than another?' He said: 'Yes, the last part of the night, so pray as much as you want until you pray Subh, then stop until the sun has risen until and it looks like a shield and (its shinning)spreads. Then pray as much as you want until an object's shadow is at its shortest, then stop until the sun passes its zenith, for Hell is stoked at midday. Then pray 'Asr, then stop until you pray 'Asr, then stop until the sun has set, for it sets between the horns of a Shaitan and rises between the horns of a Shaitan.'" [1] [1] Similar has been recorded by Muslim.