Musnad Abu Ya'la al-Mawsili 2:73

Hadaba ibn Khalid Abu Khalid narrated to us, Mubarak ibn Fudala narrated to us, he said: Abu al-Asfar narrated to me, from Sa'sa'ah ibn Mu'awiyah, who said: Uwais ibn 'Amir was from Qarn and he was from the people of Kufa, and he was among the Tabi'in. A patch of white leprosy (wadaḥ) appeared on him, so he supplicated to Allah to remove it from him, and He removed it. Then he said: "O Allah, leave for me on my body that by which I may remember Your favor upon me," so He left for him a portion of it by which he would remember His favor upon him. He was a man who would frequent the mosque with a group of his companions. He had a cousin who would frequent the authorities and was obsessed with him. If he saw him with wealthy people, he would say, "He is only trying to eat off them," and if he saw him with poor people, he would say, "He is only deceiving them." Uwais would not say anything about his cousin except good, except that when he passed by him, he would hide from him for fear that he might sin by reviling him. 'Umar ibn al-Khattab used to ask the delegations when they came to him from Kufa, "Do you know Uwais ibn 'Amir al-Qarni?" They would say, "No." Then a delegation from the people of Kufa arrived, among whom was that cousin of his. He said, "Do you know Uwais ibn 'Amir al-Qarni?" His cousin said, "O Commander of the Faithful, he is my cousin; he is a base, corrupt man who has not reached the level that you, O Commander of the Faithful, should know him." 'Umar said to him, "Woe to you, you have perished! Woe to you, you have perished! When you come to him, convey my greeting to him and command him to come to me." He arrived in Kufa and did not even take off his travel clothes before he went to the mosque. He saw Uwais and approached him. He said, "Seek forgiveness for me, O my cousin." He said, "May Allah forgive you, O cousin." He said, "And may Allah forgive you, O Uwais ibn 'Amir. The Commander of the Faithful conveys his greeting to you." He said, "And who mentioned me to the Commander of the Faithful?" He said, "He mentioned you, and he commanded us to inform you to come to him." He said, "I hear and obey the Commander of the Faithful." So he traveled to him until he entered upon 'Umar. He said, "Are you Uwais ibn 'Amir?" He said, "Yes." He said, "Are you the one who had a patch of white leprosy appear on you, so you supplicated to Allah to remove it from you, and He removed it, then you said: 'O Allah, leave for me on my body that by which I may remember Your favor upon me,' and He left for you on your body that by which you remember His favor upon you?" He said, "And what informed you of this, O Commander of the Faithful? For by Allah, no human being was aware of this." He said, "The Messenger of Allah (ﷺ) informed us that there would be a man among the Tabi'in from Qarn called Uwais ibn 'Amir, who would have a patch of white leprosy appear on him, so he would supplicate to Allah to remove it from him, and He would remove it, then he would say: 'O Allah, leave for me on my body that by which I may remember Your favor upon me,' and He would leave for him a portion of it by which he would remember His favor upon him. So whoever among you meets him, if he is able to have him seek forgiveness for him, let him do so. So seek forgiveness for me, O Uwais ibn 'Amir." He said to him, "May Allah forgive you, O Commander of the Faithful." He said, "And may Allah forgive you, O Uwais ibn 'Amir." When the people heard 'Umar say, "From the Prophet (ﷺ)," one man said, "Seek forgiveness for me, O Uwais," and another said, "Seek forgiveness for me, O Uwais." When they became too many for him, he slipped away and left, and he has not been seen until this hour.