سنن ابن ماجه

It was narrated that 'Abdullah bin 'Amr said: "We performed the Maghrib (prayer) with the Messenger of Allah, then those who went back went back, and those who stayed, stayed. Then the Messenger of Allah (ﷺ) came back in a hurry, out of breath, with his garment pulled up to his knees, and said: 'Be of good cheer, for your Lord has opened one of the gates of heaven and is boasting of you before the angels, saying: "Look at My slaves; they have fulfilled one obligatory duty and are awaiting another."