The giving of tithes and offerings is bigger than the act of giving money. Every time we give we are practicing generosity. We are teaching ourselves that every treasure we have comes from God. The act of practicing generosity becomes our worship to the Lord; our worship creates space for a promise of blessing.
The point is this: whoever sows sparingly will also reap sparingly, and whoever sows bountifully will also reap bountifully. Each one must give as he has decided in his heart, not reluctantly or under compulsion, for God loves a cheerful giver. And God is able to make all grace abound to you, so that having all sufficiency in all things at all times, you may abound in every good work. You will be enriched in every way to be generous in every way, which through us will produce thanksgiving to God.
2 Corinthians 9:6-8, 11