St. Paul the Apostle wrote:
This I say: He who sows sparingly will also reap sparingly, and he who sows bountifully will also reap bountifully. So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver.
And God is able to make all grace abound toward you, that you, always having all sufficiency in all things, have an abundance for every good work. As it is written: “He has dispersed abroad, He has given to the poor; His righteousness remains forever.”
Now may He who supplies seed to the sower, and bread for food, supply and multiply the seed you have sown and increase the fruits of your righteousness, while you are enriched in everything for all liberality, which causes thanksgiving through us to God. (2 Corinthians 9:6-11)
St. John Chrysostom said:
“Having said, therefore, when, and from whom, and how this money must be collected, the Apostle Paul entrusted the question of how much to those who contribute. He did not say: ‘Contribute such and such an amount,’ so that the command would not become burdensome, and would not give opportunity to the rich who are reluctant to give to cite poverty and cause the truly poor to say: ‘What shall we do now if we are incapable of giving?’ Rather, he confined the measure of each contribution to the ability of those who contribute. ‘Each of you,’ he says, ‘(by himself) is to put something aside and store it up, whatever he has prospered.’ And he did not say, ‘whatever he can,’ or ‘whatever is found,’ rather, ‘whatever he has prospered,’ to show that he will have the influence and favor from above as his assistants. Paul’s purpose was not only for money to be contributed to the poor, but for it to be contributed with great eagerness. Likewise, God appointed almsgiving not only for the needy to be nourished, but also for the providers to receive benefit, and much more so for the latter than for the former. For if he considered only the interest of the poor, he would have commanded solely that the money be given, and he would not have asked for the eagerness of the providers. But now you see the Apostle in every way ordering by will first and above all for the givers to be joyful: the suppliers to furnish in a cheerful manner. And at one time he says, ‘Everyone must do as he has chosen in his heart, neither out of grief nor necessity, for God loves a cheerful giver,’ not simply a giver, but the one who does this with pleasure. And again elsewhere he says, ‘…he who contributes in liberality; he who gives aid with zeal, he who does acts of mercy with cheerfulness.’ Almsgiving is precisely to give joy and to believe that you receive more than you give.” (St. John Chrysostom, ON REPENTANCE AND ALMSGIVING, pgs. 141-142)