What are the two great contrasts in this passage?
The passage contrasts the Law, which was done away, with Grace, which remains; and legalism, which demands works to merit God's favor, with the liberty wherewith Christ hath saved us. Both involve the same God but represent two totally different economies.
Les explains that the same God is behind both, yet they are two totally different economies. The Law was done away, while Grace remains. The one economy says, “Thou shalt not, Thou shalt,” while the other stands in the liberty wherewith Christ hath saved us. Les also contrasts legalism, which in any shape or form instructs you as to what you have to do to merit favor with God, with the Gospel of God’s grace. Many shun grace and say they must work for it, but Les calls that the devil’s lie. When Christ died and rose from the dead, God was totally satisfied that that was all we needed, and we can trust it completely. This remaining glory is far more glorious.