Narrated Abu Huraira (Radi Allah Anhu) Allah’s Apostle (sal-allahu-
alleihi-wasallam ) said :
“Satan puts three knots at the back of the head of any of you if he is asleep. On every knot he reads and exhales the following words, ‘The night is long, so stay asleep.’ When one wakes up and remembers Allah, one knot is undone; and when one performs ablution, the second knot is undone, and when one prays the third knot is undone and one gets up energetic with a good heart in the morning; otherwise one gets up lazy and with a mischievous heart.”
[Sahih Bukhari : Volume 2, Book 21 Prayer at Night (Tahajjud), Number 243]
Narrated ‘Abdullah (Radi Allah Anhu) : A person was mentioned before the Allah’s Apostle (sal-allahu- alleihi-wasallam ) and he was told that he had kept on sleeping till morning and had not got up for the prayer. The Prophet said, “Satan urinated in his ears.”
[Sahih Bukhari : Volume 2, Book 21 Prayer at
Night (Tahajjud), Number 245]
Narrated Abu Huraira (Radi Allah Anhu): Allah’s Apostle (sal-allahu- alleihi-wasallam ) said :“Our Lord, the Blessed, the Superior, comes every night down on the nearest Heaven to us when the last third of the night remains, saying: “Is there anyone to invoke Me, so that I may respond to invocation? Is there anyone to ask Me, so that I may grant him his request? Is there anyone seeking My forgiveness, so that I may forgive him?”
[Sahih Bukhari : Volume 2, Book 21 Prayer at Night (Tahajjud), Number 246]
source: http://inote.wordpress.com/2007/08/05/significance-of-morning-prayer/