Paul calls Christ ‘the Last Adam’ because he stands as a second head of the human race, undoing what the first Adam did. Scripture puts it plainly: ‘the first man, Adam, became a living soul; the last Adam became a life-giving spirit.’ Where the first man was from the earth, earthy, the second man is from heaven — and everyone who belongs to Adam bears his image, while everyone united to Christ will bear the image of the heavenly man.
The sermon frames this in a comparison-and-contrast structure, walking through how Adam’s sin brought death into the world and how Christ’s obedience brings life. The old church phrase ‘felix culpa’ — ‘happy fault’ — captures the theme: Adam’s fall, tragic as it was, became the occasion for a greater display of grace in the Last Adam, who reverses the curse and gives new, resurrection life to all who are joined to Him.