Sunan Ibn Majah
2791
Sahih+3

It was narrated that Tamim Ad-Dari said:“I heard the Messenger of Allah (ﷺ) say: ‘Whoever ties a horse in the cause of Allah, then feeds it with his own hand, he will have one merit for every grain.’”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi