Try this next time you’re stopped by a policeman for speeding. Try saying, “Officer, I’m sorry for speeding, but I’ve never robbed anybody. I’ve never cheated on my income tax, and I’ve stopped at every stop sign in town.”
Do you think that would work to keep yourself from getting a ticket? Probably not. The police officer would only smile as he writes it up, because he knows that no amount of obedience can make up for one act of disobedience.
That’s the way the law works. The law says, “Cursed is everyone who does not continue to do EVERYTHING written in the book of the Law” (Gal. 3:10). If you insist on putting yourself under any part of the law, then make sure you keep the whole law. Otherwise, you are under its curse.