From Abu Hurairah (radiyallaahu 'anhu) who said that Allaah's Messenger (salallaahu 'alaihi wa'sallam) said:
A man went out to visit a brother of his in a different village, so Allaah, the Most High, put an angel in wait for him in the road. So when the angel came to him he said: Where are you going? He said: I am going to visit a brother in this village. He said: Is it that you have done something for him for which you seek repayment? He said: No, it is just that I love him for Allaah's sake. He said: Then I am one sent by Allaah to you (to inform you) that Allaah, the Mighty and Majestic, loves you, just as you have loved for His sake.
[Author's text abridged hereafter]
(Paradise) cannot be attained unless the incentive for it is: