Doug Wilson in God Rest Ye Merry:
Irenaeus refers to this as recapitulation. British theologian N.T. Wright calls the Lord’s life work in this the reconstitution of Israel. Classic Reformed theology calls it the active obedience of Christ. What it means, simply, is Christ for us. In your salvation, you were not given a fraction of Christ, but rather were given all that He ever did . . . In the life of Jesus, Israel finally does it right, and He does it right on behalf of all Israel, all who are gathered to Him by faith.