Sahih Bukhari Volume 8, Book 81, Hadith 6492

حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ إِذَا نَظَرَ أَحَدُكُمْ إِلَى مَنْ فُضِّلَ عَلَيْهِ فِي الْمَالِ وَالْخَلْقِ، فَلْيَنْظُرْ إِلَى مَنْ هُوَ أَسْفَلَ مِنْهُ ‏‏مِمَّنْ فُضِّلَ عَلَيْهِ" ‏

Narrated By Abu Huraira : Allah's Apostle said, "If anyone of you looked at a person who was made superior to him in property and (in good) appearance, then he should also look at the one who is inferior to him, and to whom he has been made superior."