"But this I say: He who sows sparingly will also reap sparingly, and he who sows bountifully will also reap bountifully. 7 So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver."
One tenth of your income before tax deductions etc. belongs to God.
Additional and voluntary freewill offerings into fertile soil as well as sowing into Project Go (Missions) & Building Projects etc.