Gal. 2:21: “I do not set aside the grace of God; for if righteousness comes through the law, then Christ died in vain." Paul is concerned about righteousness beings transferred  to the believer. Gal. 3:21: “For if there had been a law given which could have given life, truly righteousness would have been by the law.”

So Paul makes it clear as one who formerly obeyed the Mosaic law strictly that no law can transfer righteousness even if we keep it to the best if our ability. righteousness can only come from the one who kept the law perfectly. Why then are there those who insist we mist keep certain law[s].

They don’t want to see Christ as the laws fulfillment so they blind themselves to the free gift of righteousness. Because one cannot adhere to both covenants it is either one or the other.  Those who had been under the law had been delivered from it (Rom. 7:6) that they are dead to it (Rom. 7:4). We as believers are not under the law any longer, but under grace (Rom.. 6:14). We are warned that the Christian who seeks to keep the law to be justified or sanctified have fallen from grace (Gal 5:4). So why are there still those who insist one must keep the Old Testament law that was given to Moses?

Several reasons, they are taught wrong by their church, they misunderstand the covenants  and how they work; what laws are re-ratified in Christ and what are not. Or they just have not looked into the topic yet, or they are lazy and are satisfied and don’t care to change… there are numerous reasons, the bottom line is they are wrong and are harming themselves and others if they spread this Galatian error (Paul addressed the Judaizers in the book of Galatian's on believing in Christ and still holding to the law).

It is pointed out by Sabbath keepers that Jesus worshipped on Saturday 1,700 times. Jesus also went to the temple, we do not go to temple; we are a new entity, the church. If Christ is our example He also kept the entire ceremonial Law of Moses. Do law keepers keep this? No; bad arguments do not help their position, but they have an arsenal of them.

Another law keepers argument is, if we don’t obey the 10 commandments today then we can steal and lie, we can go kill someone and commit adultery etc. They overlook that there are many wrongs which the Decalogue does not address. According to their own logic, we then can become a drunkard and a homosexual since it is not the 10 but the Law of Moses ( those other 603 commands they ignore for the 10 only) that speaks against this. They say it was done away with. So their argument is a bad one.

Another bad argument is having the 10 commandments have a greater significance because “What God wrote with his own finger is eternal and what Moses wrote is not.” One cannot separate any command from the rest because they were written by God’s finger. He commanded Israel to obey them all. Does anyone in the Old Testament hold to the 10 commandments as separate from the rest of the law and ordinances after they were all given? Where does the Bible give the 10 priority above all the others? They were all a unit called the law of Moses, just as they are referred to in the New Testament by Jesus. What do they say when we find the original commands God wrote with his own finger broken and Moses himself rewriting the 10 again on the tablets (Ex.34:27-28; Ex. 31:23). I guess one must overlook that small detail  that infringes on their legal argument.

This is why Sceripture says in Neh. 9:13-14: “You came down also on Mount Sinai, and spoke with them from heaven, and gave them just ordinances and true laws, good statutes and commandments. You made known to them Your holy Sabbath, and commanded them precepts, statutes and laws, by the hand of Moses Your servant.” This is exactly what Jn.1:17 states, “the law came through Moses.”

Paul describes the Mosaic covenant in 2 Cor.3: 7. (the Ten Commandments) with the covenant "done away" in Christ." If you are in Christ you are NOT to be keeping the Old covenant. Why? Because one cannot be faithful to Christ and at the same time Hold to Moses.