"To give to God is to take from God's right hand and put that very thing back into God's left hand" -Miroslav Volf
The Pharisee in me demands that I give to God. This giving on my behalf is required of me in order to get something in return; God's love and acceptance, a job opportunity, the warm-fuzzies, a ticket to heaven, or the love and admiration of people. The Pharisee in me says, 'You better give to God by following these rules, or else _____________ (fill in horrid results here)".
We fail to see that whatever we may be able to give to God, whether it is given in a moment of fear and doubt, or out of some warped expectation that God may "return the favor", or even out of genuine worship, could not be given by us if He did not give it first.
God is the giver. We give nothing to him that he needs, or demands. Yes, it's true; God doesn't need you. Whatever God gives or does for us, is out of complete and perfect love for his children.