I don't believe that there is a curse for not tithing. Jesus took the law and ALL of it's requirements. Jesus took the curse fully upon himself. Paul even said that if you trust in the old Law and it's commandments you fall under it's curse. I think it's cool how Abraham tithed to Melchizedek long before the levitical law that most of the church still practices today. He did this in love and appreciation not because of any Law except the Law of Love. Melchizedek is believed by many to be a symbol of Jesus if not Jesus himself. So I think that when we are under the Law of Christ and not under the false comfort of being under the Levitical law. Jesus will ask so much more than 10%. His Law is Love. ALL YOUR MONEY, ALL YOUR TIME are His and go to His people. This is the Law that we are under. The Law of sacrificial Love.