2 Corinthians 9:5, 7

I thought it necessary therefore to entreat the brethren, that they would go before unto you, and make up beforehand your aforepromised bounty, that the same might be ready as a matter of bounty, and not of extortion.

Let each man do according as he hath purposed in his heart: not grudgingly, or of necessity: for God loveth a cheerful giver.