Sahih Bukhari
One-fifth of Booty to the Cause of Allah (Khumus)
Volume: 004 / Book Number: 053 / Hadith Number: 347
Narrated Khaula Al-Ansariya:
I heard Allah's Apostle saying, "Some people spend Allah's Wealth (i.e. Muslim's wealth) in an unjust manner; such people will be put in the (Hell) Fire on the Day of Resurrection."