Musnad Ahmad 28:355

Rawh narrated to us, al-Awza’i narrated to us, from Hassan ibn ‘Atiyyah, from Abu Kabshah al-Saluli, from ‘Abdullah ibn ‘Amr ibn al-‘As, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "There are forty good deeds, the highest of which is the lending of a milking goat. No servant performs any of these good deeds, hoping for its reward and believing in its promise, but that Allah will cause him to enter Paradise because of it."