2 Corinthians 9:6-8
Remember this: Whoever sows sparingly will also reap sparingly, and whoever sows generously will also reap generously. Each of you should give what you have decided in your heart to give, not reluctantly or under compulsion, for God loves a cheerful giver.
So, when we give, we simply offer him a small portion of the abundance he has already given to us. Giving is an expression of our thankfulness and praise to God. It comes from a heart of worship that recognizes everything we have and give already belongs to the Lord.