What the bible says about tithes and offerings...
Malachi 3:7-12 (HCSB)
7 “Since the days of your fathers, you have turned from My statutes; you have not kept ⌊them⌋. Return to Me, and I will return to you,” says the LORD of Hosts. But you ask: “How can we return?”8 “Will a man rob God? Yet you are robbing Me!” You ask: “How do we rob ]You?” “⌊By not making the payments⌋ of the tenth and the contributions. 9 You are suffering under a curse, yet you—the whole nation—are ⌊still⌋ robbing Me. 10 Bring the full tenth into the storehouse so that there may be food in My house. Test Me in this way,” says the LORD of Hosts. “See if I will not open the floodgates of heaven and pour out a blessing for you without measure. 11 I will rebuke the devourer for you, so that it will not ruin the produce of your land and your vine in your field will not fail to produce fruit,” says the LORD of Hosts. 12 “Then all the nations will consider you fortunate, for you will be a delightful land,” says the LORD of Hosts.
2 Corinthians 9:6-7 (HCSB)
6 Remember this: The person who sows sparingly will also reap sparingly, and the person who sows generously will also reap generously. 7 Each person should do as he has decided in his heart—not reluctantly or out of necessity, for God loves a cheerful giver.