2 Corinthians 9:5-7

5Therefore I thought it necessary to exhort the brethren to go to you ahead of time, and prepare your generous gift beforehand, which you had previously promised, that it may be ready as a matter of generosity and not as a grudging obligation.

6But this I say: He who sows sparingly will also reap sparingly, and he who sows bountifully will also reap bountifully.

7So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver.