How did Christ's righteousness bring the free gift of justification after Adam's fall?

Les explains that Paul's "therefore" calls the reader back to what he already said: salvation cannot be by anything man can do, but is all accomplished by Christ's work of the cross. God is just in being the justifier of those who believe; He is not cutting corners or winking at man's sin, but has paid the total price. Romans 5:18 contrasts Adam and Christ: by one offense judgment and condemnation came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification. As Adam caused us to fall, Christ has made it possible to lift us up. Les also connects this to Ephesians 2, where those who were dead in trespasses and sins because of Adam are quickened or made alive, having walked according to the course of this world and the prince of the power of the air, with unbelievers blinded by the god of this world.