All of I Corinthians 9, II Corinthians 8, and II Corinthians 9 are taken up with this subject. But there are not commands to the people of God anywhere in the New Testament about how much we are to give, when we are to give, or where we are to give. Like all other acts of worship, giving is an act of grace. It must be free and voluntary. But there are some plain, simple guidelines laid down in the New Testament for us to follow.
Love needs no law.
It is a law unto itself. It is the most powerful and most generous of all motives. If that which you give arises from a willing heart, if it is given freely and cheerfully, it is accepted of God. We are expected to give generously in accordance with our own ability. Men and women, rich and poor, old and young, all who are saved by the grace of God are expected to give for the support of God's church and kingdom.