Musnad Ahmad 551:7

Aswad ibn Amir narrated to us, he said: Jarir—meaning Ibn Hazim—narrated to us, he said: I heard al-Hasan, he said: A man said to Amr ibn al-Aas: "Do you see a man whom the Messenger of Allah, peace and blessings of Allah be upon him, died while he loved him—is he not a righteous man?" He said: "Yes." He said: "The Messenger of Allah, peace and blessings of Allah be upon him, died while he loved you, and he had appointed you to a position of authority." He said: "He did appoint me, but by Allah, I do not know if it was love for me on his part, or if it was seeking my assistance. However, I will tell you about two men whom the Messenger of Allah, peace and blessings of Allah be upon him, died while he loved them: Abdullah ibn Mas'ud and Ammar ibn Yasir."