From Sahih Muslim (Hadith 5238):
Abu Bakr Siddiq reported:As we went along with Allah's Messenger (ﷺ) from Mecca to Medina, we passed by a shepherd and Allah's Messenger (ﷺ) was feeling thirsty. He (Abu Bakr Siddiq) said: I milked for him a small quantity of milk (from his goat) and brought it to him (the Holy Prophet), and he drank it and I was very happy
Reference: Muslim 5238