Sahih Muslim 2542 a
Usair b. Jabir reported that a delegation from Kufa came to 'Umar and there was a person amongst them who jeered at Uwais. Thereupon Umar said:
Is there amongst us one from Qaran? That person came and Umar said: Verily Allah's Messenger (ﷺ) has said: There would come to you a person from Yemen who would be called Uwais and he would leave none in Yemen (behind him) except his mother, and he would have the whiteness (due to leprosy) and he supplicated Allah and it was cured except for the size of a dinar or dirham. He who amongst you meets him should ask him to supplicate for forgiveness (from Allah) for you.
حَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا هَاشِمُ بْنُ الْقَاسِمِ، حَدَّثَنَا سُلَيْمَانُ بْنُ الْمُغِيرَةِ، حَدَّثَنِي 
 سَعِيدٌ الْجُرَيْرِيُّ، عَنْ أَبِي نَضْرَةَ، عَنْ أُسَيْرِ بْنِ جَابِرٍ، أَنَّ أَهْلَ الْكُوفَةِ، وَفَدُوا، إِلَى عُمَرَ وَفِيهِمْ
 رَجُلٌ مِمَّنْ كَانَ يَسْخَرُ بِأُوَيْسٍ فَقَالَ عُمَرُ هَلْ هَا هُنَا أَحَدٌ مِنَ الْقَرَنِيِّينَ فَجَاءَ ذَلِكَ الرَّجُلُ
 فَقَالَ عُمَرُ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَدْ قَالَ ‏
"‏ إِنَّ رَجُلاً يَأْتِيكُمْ مِنَ الْيَمَنِ يُقَالُ
 لَهُ أُوَيْسٌ لاَ يَدَعُ بِالْيَمَنِ غَيْرَ أُمٍّ لَهُ قَدْ كَانَ بِهِ بَيَاضٌ فَدَعَا اللَّهَ فَأَذْهَبَهُ عَنْهُ إِلاَّ مَوْضِعَ
 الدِّينَارِ أَوِ الدِّرْهَمِ فَمَنْ لَقِيَهُ مِنْكُمْ فَلْيَسْتَغْفِرْ لَكُمْ ‏"‏ ‏.‏