What shall we say then? Are we to continue in sin so that grace may increase? May it never be! How shall we who died to sin still live in it?
Romans 6:1-2 ~~ Paul issues the authoritative smack-down of the antinomian heresy.
Romans 6:3-5 ~~ Paul speaks of the atonement and the sacraments in this passage. "Do you not know that all of us who have been baptized into Christ Jesus have been baptized into His death? Therefore we have been buried with Him through baptism into that, so that as Christ was raised from the dead through the glory of the Father, so we too might walk in the newness of life." This passage indicates that the crucial moment of atonement, the prime salvific event, is not defined by the Cross. By dying Christ triumphed over death; by living, Christ ensured the future resurrection of the body. Baptism unites us to Christ in recapitulating the Cross, but it is His Resurrection that gives us eternal life.
Romans 6:5-11 ~~ An extended meditation on the passion and death of Christ, and how that transforms our lives by enabling us to die to sin by dying and living in Him.
Romans 6:7 ~~ "For he who has died is freed from sin." This is integral to the passage as a whole, but I can't help but think of it atomistically, as an general principle unto itself. This would have pretty serious ramifications to our theology of suffering and death, though I'm not sure if I could do such ideas justice here.
Romans 6:16-19 ~~ Paul applies the metaphor of slavery both to our prior condition of sinfulness, and to our redeemed condition of sanctity. He clarifies that "I am speaking in human terms because of the weakness of your flesh." In Galatians, he contrasts between our slavery to sin and our sonship in Christ, which is a much more powerful and liberating analogy. On the other hand, that passage was primarily about the doctrine of liberty, whereas this passage seeks to counter the antinomian heresy (that advocates freedom even to sin) and therefore emphasizes our obedience. When our heart belongs to God, all things are lawful (though not all things are profitable; cf. 1 Corinthians 10:23). When our hearts wrestle with sin, we must be very careful indeed.
Romans 6:22 ~~ It's a limited analogy, pertaining to our weakness in the flesh, but it still carries weight. "But now, having been freed from sin and enslaved to God, you derive the benefit, resulting in sanctification, and the outcome, eternal life." The verse that follows is better known, but this one's pretty spectacular as well. It should be noted that the following verse only speaks to our slavery to God (and thus, only to grace received as a free gift) rather than our sonship in Christ (and thus to the grace and glory that has become our inheritance).
For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.