Commenting on Galatians 5:19, Martin Luther wrote:
So dangerous a plague is it to trust in one’s own righteousness and to dream that one is pure. But we are not in a position to trust in our own righteousness, for we are aware of the uncleanness of the flesh. This awareness humbles us, so that we hang our heads and cannot trust in our own good works; and it compels us to run to Christ the Propitiator, who does not have a corrupt or blemished flesh but has an altogether pure and holy flesh, which He gave for the life of the world. In Him we find a righteousness that is complete and perfect. Thus we abide in a humility that is not fictitious or monastic but authentic, because of the filth and the faults that cling to our flesh; if God wanted to judge severely, we would deserve eternal punishment on account of these. We are not proud in the sight of God, but we acknowledge our sins humbly and with a contrite heart; and we seek forgiveness, rely on the benefaction of Christ the Mediator, move into the presence of God, and pray that our sins be forgiven on His account. Therefore God stretches the immense heaven of grace over us and for the sake of Christ does not impute to us the remnants of sin that cling to our flesh.
Luther, Martin Luther’s Works, v. 27, Lectures on Galatians 86