Jason Dohm explains in this video that many times, Christians can be discouraged by their ongoing, besetting sins. Sin is not as complex as we may make it out to be. God has given us the law to be a tutor and bring us to Christ. Christ is our solution to a Christian's struggle with sin. We should never rely on our own strength or willpower to overcome sin. Christ has already triumphed over sin!
James 4:17 (NKJV) - "Therefore, to him who knows to do good and does not do it, to him it is sin."
Many times Christians are discouraged by their besetting sins. In other words, their ongoing sins are a big discouragement for Christians. But normally they're thinking primarily about the wrong sins. Really, they're not tracing it back to its relationship to the great commandment. When Jesus was asked, which is the great commandment, he quoted Deuteronomy 6, You shall love the Lord your God with all your heart, with all your soul, with all your strength.
And the other commandments just roll up to this one. So our problems are very fundamental. They're not as complex as we'd like to think they are, or as we make them out to be. It simply has to do with the great commandment, love for God. The good news is that God has given us the law to be a tutor to bring us to Christ.
In other words, the law brings us kicking and screaming to Christ. As simplistic as it sounds, Christ is the great solution to Christians' problems. Their besetting sins are not their biggest problem. It's upstream from there. It's with the great commandment and love of God.