Ya'la b. Umayya said: I remarked to ‘Umar b. al-Khattab that God had said, “You may shorten the prayer,” only “if you fear those who are infidels may afflict you” (Al-Qur’an; 4:101), whereas the people were now safe. He replied that he had wondered about the same matter, so he asked God's Messenger and received the reply, “It is an act of charity which God has done to you, so accept His charity.” Muslim transmitted it.