From the book ‘Whole Bible Christianity’
The letter from Paul to the assemblies of Galatia is right up there with difficult things that the untaught and unstable distort (2 Peter 3:16). Most of the time, this book is presented as a teaching against God’s Laws. But when we get into the book, and read carefully, we find that Paul is not telling us to ignore God’s Word, especially the Law. What he is doing is contrasting merit with grace through faith. The key verse says it all.
4You have been severed from Christ, you who are seeking to be justified by law; you have fallen from grace. (Galatians 5:4 NASB95)
Some of the Galatians were seeking to be justified by their own actions (or doing what was right in their own eyes), when they were already justified through the blood of the Lamb. Trading on one’s own merit renders the sacrifice of the Christ useless. Merit is the idea that we have earned something, like wages for work. Some try to trade their (perceived) merit for eternal life. This is a mistake because it’s just not worth it to God. If we can be justified on our own merit by circumcising a little piece of skin, then we should just go the whole way and cut it all off. Then we will be really, really justified!
In other words, Paul is saying that following Laws (especially circumcision, meaning to become a Jew) is not the way to gain a place in God’s kingdom. It is only by grace through faith that anybody – Jew or Gentile, circumcised or not – has a place at all. The Law is for living after salvation, not the means to get it.