Abram tithed before there was a law to tithe, he was not under 'mandate' to tithe. He did it out of love for God. He gave His son to die for us out of love, then out of love we should do the things He has asked us to do. If you claim to love God with all your heart, all your soul, all your spirit, then He should not have to make you tithe, you should tithe because you Love Him. If you say you love God then show Him!
