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. – 2 Corinthians 9:7 

For if the willingness is there, the gift is acceptable according to what one has, not according to what one does not have. – 2 Corinthians 8:12  

“Bring the whole tithe into the storehouse, that there may be food in my house. Test me in this,” says the Lord Almighty, “and see if I will not throw open the floodgates of heaven and pour out so much blessing that there will not be room enough to store it.” – Malachi 3:10