Already been said. Jesus did say that He did NOT come to abolish the Law. It is all there. Only that we will not be judged under it.
Did NOT come to abolish, meaning perhaps that it applies. No, not all the punishments and judgements. Jesus did that for us. Yet the Law remains to follow best we can.
Perhaps the story of the widow and the two mites needs dusted off.
Should you choose not to tithe, not to give God what He has asked for, that is between you and He. Personally, I trust God with my funds. I wish more did.