Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 1195
Narated By Ya'la b. Umayyah : I remarked to 'Umar b. al-Khattab: Have you seen the shortening of the prayer by the people today while Allah has said; "If you fear that those who are infidels may afflict you" (iv. 101), whereas those days are gone now? He replied: I have wondered about the same matter for which you wondered. So I mentioned this to the Apostle of Allah (pbuh). He said: It is an act of charity which Allah has done to you, so accept His charity.