Sahih Bukhari Volume 4, Book 54, Hadith Number 479.

Narated By Sahl bin Sad : The Prophet said, “Paradise has eight gates, and one of them is called Ar-Raiyan through which none will enter but those who observe fasting.” The Prophet also said, “If a person spends two different kinds of something (for Allah’s Cause), he will be called from the gates of Paradise.”