The grace of God and the gift that consists of the favour of that one Man Jesus Christ far surpasses the death that came over all human beings through the transgression of Adam.
This gift of God therefore comes via a different route than death, which entered via the sin of one man (Romans 5:16). The gift (of acquittal and reconciliation) given by God counters the condemnation. Many transgressions are thereby absolved. Thomson1 deems this verse, which highlights the inequality between Adam and Christ, as the core of what he regards as a structurally chiastic pericope. In Romans 5:6 Paul had said that Christ's death was still on time for the ungodly. He now says something similar in Romans 5:16. God’s justification is an overwhelming counter-revolutionary force in an otherwise condemned world: Adam let sin loose on the earth, but God turns its fate around.2
16 And the free gift is not like the result of that one man’s sin. For the judgment following one trespass brought condemnation, but the free gift following many trespasses brought justification.