Riyad as-Salihin

Abu Mas'ud (May Allah be pleased with him) reported: A man came to the Prophet (ﷺ) with a she-camel wearing a nose-string and said: "This is (a gift) in the Cause of Allah." The Messenger of Allah (ﷺ) replied, "You will have in return for it on the Day of Resurrection seven hundred she-camels and every one of them will be wearing a nose-string."

[Muslim].