Matthew Henry Commentary 1 Timothy 1:5-11

"But the end of the charge is love out of a pure heart and a good conscience and faith unfeigned: from which things some having swerved have turned aside unto vain talking; desiring to be teachers of the law, though they understand neither what they say, nor whereof they confidently affirm. But we know that the law is good, if a man use it lawfully, as knowing this, that law is not made for a righteous man, but for the lawless and unruly, for the ungodly and sinners, for the unholy and profane, for murderers of fathers and murderers of mothers, for manslayers, for fornicators, for abusers of themselves with men, for menstealers, for liars, for false swearers, and if there be any other thing contrary to the sound doctrine; according to the gospel of the glory of the blessed God, which was committed to my trust." — 1 Timothy 1:5-11 (ASV)

Whatever tends to weaken love for God, or love for fellow believers, tends to defeat the purpose of the commandment. The purpose of the gospel is fulfilled when sinners, through repentance towards God and faith in Jesus Christ, are brought to practice Christian love. And since believers were righteous people in God's appointed way, the law was not against them. But unless we are made righteous by faith in Christ, truly repenting and forsaking sin, we are still under the curse of the law, even according to the gospel of the blessed God, and are unfit to share the holy happiness of heaven.