Galatians 2:17

But if, while we sought to be justified in Christ, we ourselves also were found sinners, is Christ a minister of sin? God forbid.

This is somewhat parenthetical to clear up any possible misunderstanding. Paul had just laid down the gospel that we are justified by the faith of Christ; and, in order to prevent any man from thinking that his own fidelity and compliance with Christ's teaching were not needed, Paul effectively denied such a thought with this verse. Christians are not saved in their sins but from their sins. And holiness is an attainment without which no man shall see the Lord. This does not imply that one has to be perfect, an impossibility anyway, but it does teach that a man must do his best to serve God. God will supply whatever is lacking on the Christian's part, so that at last every man shall be accounted "saved by grace" and not by any merit whatever.