Prayer (Kitab Al-Salat): Detailed Rules of Law about the Prayer during Journey
Dawud :: Book 4 : Hadith 1293
Narrated Abdullah ibn Amr:
AbulJawza' said: A man who attended the company of the Prophet (peace_be_upon_him) narrated to me (it is thought that he was Abdullah ibn Amr): The Prophet (peace_be_upon_him) said to me: Come to me tomorrow; I shall give you something, I shall give you something, I shall reward you something, I shall donate something to you. I thought that he would give me some present.
He said (to me when I came to him): When the day declines, stand up and pray four rak'ahs. He then narrated something similar.
This version adds: Do not stand until you glorify Allah ten times, and praise Him ten times, and exalt Him ten times, and say, "There is no god but Allah" ten times. Then you should do that in four rak'ahs. If you are the greatest sinner on earth, you will be forgiven (by Allah) on account of this (prayer).
I asked: If I cannot pray this the appointed hour, (what should I do)? He replied: Pray that by night or by day (at any time).