The Book of Prayers (Kitab Al-Salat)

Muslim :: Book 4 : Hadith 1773

'A'isha reported: The Messenger of Allah (may peace be upon him) sent a man in charge of an expedition and he would recite for his Companions during their prayer, ending (recitation) with:" Say, He is God, One." When they returned mention was made of it to the Messenger of Allah (may peace be upon him). He (the Holy Prophet) told them to ask him why he had done like that. So they asked him and he said: Verily, it is an attribute of the Compassionate One, and (for this reason) I love to recite it. The Messenger of Allah (may peace be upon him) thereupon said: Inform him that Allah loves him.