Sunan an-Nasa'i, Volume 4, Book 28, Hadith 3604 (DarusSalam) ⓘ
It was narrated that 'Urwah Al-Bariqi said: "The Messenger of Allah said: 'Goodness is tied to the forelocks of horses until the Day of Resurrection.'"
حَدَّثَنَا مُحَمَّدُ بْنُ الْعَلاَءِ أَبُو كُرَيْبٍ، قَالَ حَدَّثَنَا ابْنُ إِدْرِيسَ، عَنْ حُصَيْنٍ، عَنْ عَامِرٍ، عَنْ عُرْوَةَ الْبَارِقِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْخَيْلُ مَعْقُودٌ فِي نَوَاصِيهَا الْخَيْرُ إِلَى يَوْمِ الْقِيَامَةِ " .
also referenced under: Hadith 3574 (Reference) & Book 28, Hadith 14 (In-Book)