[24] There is one who scatters, yet increases more; And there is one who withholds more than is right, but it leads to poverty. [25] The generous soul will be made rich, and he who waters will also be watered himself. [26] The people will curse him who withholds grain, but blessing will be on the head of him who sells it.
I once heard that you can't give or receive blessings with a closed hand. As someone who has tested God on the matter, I can attest to this without question. I never doubt God's faithfulness (even though I have questioned His plans and His timing). He has been beyond faithful to honor our giving in abundance.
God doesn't owe me anything. I certainly don't deserve any of the good He does for me, but He is such a gracious Father. I have yet to experience having less when I give more. Whether it be time or money, He meets and exceeds all of our needs. I am convinced you can't out-give God. All of it is His to start with.