Sahih Bukhari Volume 4, Book 52, Hadith Number 94.

Narated By Abu Huraira : The Prophet said, “Whoever spends two things in Allah’s Cause, will be called by all the gate-keepers of Paradise who will be saying, ‘O so-and-so! Come here.’ ” Abu Bakr said, “O Allah’s Apostle! Such persons will never be destroyed.” The Prophet said, “I hope you will be one of them.”