Sahih Muslim Book 18, Hadith Number 4290.

Chapter : It Is meritorious to spend the surplus wealth for one’s brother.

Abu Sa’id al-Khudri reported: While we were with the Apostle of Allah (may peace be upon him) on a journey, a person came upon his mount and began to stare on the right and on the left, (it was at this moment) that Allah’s Messenger (may peace be upon him) said: He who has an extra mount should give that to one who has no mount for him, and he who has surplus of provisions should give them to him who has no provisions, and he made mention of so many kinds of wealth until we were of the opinion that none of us has any right over the surplus.