Sahih al-Bukhari 2849
Sahih al-Bukhari · Book 56: Fighting for the Cause of Allah (Jihaad) · Good will remain in the forelocks of horses
Narrated `Abdullah bin `Umar:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ ، حَدَّثَنَا مَالِكٌ ، عَنْ نَافِعٍ ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْخَيْلُ فِي نَوَاصِيهَا الْخَيْرُ إِلَى يَوْمِ الْقِيَامَةِ " .
Allah's Messenger (ﷺ) said, "Good will remain (as a permanent quality) in the foreheads of horses till the Day of Resurrection."