Sahih Muslim 2403 a

Abu Musa al-Ash'ari reported that while Allah's Messenger (ﷺ) was in one of the gardens of Medina, reclining against a pillow and fixing a stick in a mud, that a person came asking for the gate to be opened, whereupon he said: Open it for him and give him glad tidings of Paradise and, lo, it was Abu Bakr. I opened (the gate) for him and gave him the glad tidings of Paradise. Then another person asked for the door to be opened, whereupon he said: Open it and give him the glad tidings of Piradise. He said: I went away and, lo, it was 'Umar. I opened it for him and gave him the glad tidings of Paradise. Then still another man asked for the door to be opened, and thereupon Allah's Messenger (ﷺ) said: Open it and give him the glad tidings of Paradise after a trial would afflict him. I went and, lo, it was 'Uthman b. 'Affan. 1 opened the door and gave him the glad tidings of Paradise and informed him (what the Prophet (ﷺ) had said). Thereupon he said: O Allah, grant me steadfastness. Allah is one Whose help is to be sought.