Therefore, if anyone is united with the Messiah, he is a new creation — the old has passed; look, what has come is fresh and new! 2 Corinthians 5:17 CJB
Regeneration, which consists of two things; namely, 1. Weanedness from the world: “Henceforth we know no man after the flesh, v. 16. We do not own nor affect any person or thing in this world for carnal ends and outward advantage: we are enabled, by divine grace, not to mind nor regard this world, nor the things of this world, but to live above it. The love of Christ is in our hearts, and the world is under our feet.” Note, Good Christians must enjoy the comforts of this life, and their relations in this world, with a holy indifference. Yea, though we have known Christ after the flesh, yet, says the apostle, we know him no more. It is questioned whether Paul had seen Christ in the flesh. However, the rest of the apostles had, and so might some among those he was now writing to. However, he would not have them value themselves upon that account; for even the bodily presence of Christ is not to be desired nor doted upon by his disciples. We must live upon his spiritual presence, and the comfort it affords. Note, Those who make images of Christ, and use them in their worship, do not take the way that God has appointed for strengthening their faith and quickening their affections; for it is the will of God that we should not know Christ any more after the flesh. 2. A thorough change of the heart: For if any man be in Christ, if any man be a Christian indeed, and will approve himself such, he is, or he must be, a new creature, v. 17. Some read it, Let him be a new creature. This ought to be the care of all who profess the Christian faith, that they be new creatures; not only that they have a new name, and wear a new livery, but that they have a new heart and new nature. And so great is the change the grace of God makes in the soul, that, as it follows, old things are passed away—old thoughts, old principles, and old practices, are passed away; and all these things must become new. Note, Regenerating grace creates a new world in the soul; all things are new. The renewed man acts from new principles, by new rules, with new ends, and in new company.