Now then, why do you try to test God by putting on the necks of Gentiles a yoke that neither we or our ancestors have been able to bear? Acts 15:10
There is a widespread belief that the Old Covenant God made with Israel through Moses was a way to show men how to obtain salvation. Keep the law and get saved. But, since Israel did not keep the law, God cast them off and tried the New Covenant.
I wish to say that no one was ever saved by keeping the law. The law was never intended as a means of salvation. Seth, Abraham, and Isaac were saved long before the law was given. They were saved through faith, as is every person who was ever saved. When I hear people say that they live by the ten commandments, or maybe by the sermon on the mount, my feeling is that they should get them out and read them again.
Once I was trying to witness to an old lady (in vain). She said she would make it on moral grounds. She was not so bad after all. "I've never murdered anyone," she told me. Wow! I should have congratulated her. I mean never murdered anyone? How good can a person get?
I'm just "funning around", of course, while listening to people talk about their self-saving virtue. As if I expect to see a halo around the head of one who has not murdered.
Have you ever asked one who says they follow the sermon on the mount if they ever give "no thought for the morrow"? Have they cashed in all their insurance policies? We soon become weary of such posturing. James tells us that if we break any part of the law (James 2:10), we are guilty of breaking it all. So much for the righteousness of mankind.
The law, telling of the righteousness of God, condemns, but cannot justify. Paul tells us how he was blameless according to the law, but throws himself on the mercy of God as a sinner.
I totally love chapter 15 of Acts. If read, it shows that we are not under the law, but in need of salvation through faith. We do not need more rules to follow, but God's mercy.