Narrated Ibn 'Abbas:
that the Prophet (ﷺ) said: "My Lord, Blessed is He and Most High, came to me in the best of appearances. So he said: 'O Muhammad!' I said: 'Here I am O my Lord! And I am at Your service.' He said: 'What is it that the most exalted group busy themselves with?' I said: '[Lord] I do not know.' So He placed His Hand between my shoulders, until I sensed its coolness between my breast, so I knew what was in between the east and the west. He said: 'O Muhammad!' I said: 'Here I am O my Lord! And I am at Your service.' He said: 'What is it that the most exalted group busy themselves with?' I said: 'In the acts that raise ranks and the acts that atone, and in recording the footsteps to the congregation, Isbagh Al-Wudu in difficulties, and awaiting the Salat after the Salat. And whoever preserves them, he shall live in goodness and die upon goodness, and his sins shall be like that on the day upon which his mother bore him.'"
English reference: Vol. 5, Book 44, Hadith 3234
Arabic reference: Book 47, Hadith 3542