Musnad Ahmad 788:25

'Abd al-Razzaq narrated to us, Ma'mar informed us, from Qatadah, from Abu 'Uthman al-Nahdi, from Abu Musa al-Ash'ari, who said: I was with the Prophet, peace and blessings of Allah be upon him—I think he said—in a garden. A man came and gave the greeting of peace. The Prophet, peace and blessings of Allah be upon him, said: "Go and give him permission, and give him glad tidings of Paradise." So I went, and it was Abu Bakr, may Allah be pleased with him. I said: "Enter, and receive glad tidings of Paradise." He continued to praise Allah, the Mighty and Majestic, until he sat down. Then another came and gave the greeting of peace. He said: "Give him permission, and give him glad tidings of Paradise." So I went, and it was 'Umar ibn al-Khattab, may Allah be pleased with him. I said: "Enter, and receive glad tidings of Paradise." He continued to praise Allah, the Mighty and Majestic, until he sat down. Then another came and gave the greeting of peace. He said: "Go and give him permission, and give him glad tidings of Paradise upon a severe trial." He said: So I went, and it was 'Uthman. I said: "Enter, and receive glad tidings of Paradise upon a severe trial." He said: So he began to say: "O Allah, grant patience," until he sat down.