Realize what Jesus said in Matthew 5:17-20 is vital - we do not have the authority to relax anything which is found in the NT.

It certainly is but you have failed to understand it. Jesus fulfilled the law. He is the only man to ever have done so. It is by his fulfillment of the law that you are saved, not by your own. If you fail to understand that , then you are still living under the old covenant which has grown old and is ready to pass away. Under that old covenant, you will be judged by your acts and there is no person who can satisfy those requirements. If righteousness came by the law, than Christ has died in vain.

You must understand that you are saved by grace alone, not your obedience, or you have missed the entire New Testament. It is an understanding of grace and who you are because of it that will cause you to obey God's laws. It is not your obedience of laws that cause you to be saved.