ENOfficial
Ibn ‘Abbas reported God's Messenger as saying, “The most favored horses are the sorrel.” Tirmidhi and Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنِ ابْنِ عَبَّاسٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «يُمْنُ الْخَيْلِ فِي الشُّقْرِ» . رَوَاهُ الترمذيُّ وَأَبُو دَاوُد
sunnah.com