Zakat (Kitab Al-Zakat)
Dawud :: Book 9 : Hadith 1679
Narrated Abdullah ibn Amr ibn al-'As:
The Prophet (peace_be_upon_him) said: There are forty characteristics; the highest of them is to give a goat on loan (for benefiting from its milk). If any man carries out any of those characteristics with the hope of getting a reward and testifying to the promise for it, Allah will admit him to Paradise for it.