1 Corinthians 16:2
On the first day of the week, each of you is to set something aside and save in keeping with how he prospers, so that no collections will need to be made when I come.
Two things: FIRST and AS HE PROSPERS
FIRST: Let your giving determine your living. Give to Him first. Off the top, from your first and from your best. Do not keep back the first and best for yourself. Set it ASIDE for the Lord who is the first and best.
AS HE PROSPERS: However you prosper, it is from God. If you prosper more, He has given you more to give. Do you see it that way or do you see it as more to keep for yourself?
If your life is oriented around money, you will keep the first and best for yourself and even if you give, you will only give what you feel like, not in proportion to how He prospers you.