The Reformation is about God's gracious forgiveness of our sins - not about anti-Catholicism. Before this Word is spoken, we are possessed and oppressed by our sin, which was brought to life by the Law (Romans 7). Looking into this perfect Law of God, we always see our inability to reach it. No matter how hard we work, how much good we do, we cannot obtain the righteousness of God. The Law's demands - even love of neighbor - we cannot keep.
In this light, look at the Gospel text. Jesus is speaking of slavery to sin, of the heart and conscience, that gives birth to death. From this we cannot free ourselves; it is indeed a body of death, a corpse affixed to us. Particularly: personal sins - unmet spousal demands, a rebellious child - that we bring to God, our shoulders slumped. That is our slavery.
Abide in My word, says Jesus, and we as disciples will know the Truth that frees the conscience. Once this happens, we see "the righteousness of God" not as Law but as a Gospel gift! We don't do it; it is given to us apart from the Law. Christ's atoning sacrifice effected it; we are now sons of God, inheritors of His infinite gift of salvation. Drink now the Blood, the vessel of His mercy.
Soli Deo gloria.