2 Corinthians 5:17, Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come.
This must be read in its immediate context. Prior to this, Paul wrote on the ministry of the new covenant, which has not come by the letter (such as with ink or tablets like it was with Moses), but by the Spirit (3:6). Paul refers to the old covenant as “the ministry of death,” which appeared in so much glory that the Israelites could not look upon Moses’ face (3:7; Exodus 34:29-35). (Paul’s “ministry of death” language matches that of Romans 7:9-12 where Paul says the law kills.) Since this ministry of death appeared in such glory, Paul says, how much more glorious will the new covenant appear? “For if there was glory in the ministry of condemnation, the ministry of righteousness must far exceed its glory” (3:9). Paul even goes so far to say the old covenant no longer has any glory because the glory of the new covenant far surpasses it (3:10). Furthermore, Paul says, since the old covenant that came to an end had glory, then how much more glory the new covenant will have since it’s permanent (3:11).
Paul goes on to explain that this permanent, new covenant is in Christ. The old covenant of Moses has passed; the new covenant has come in Christ, and unlike the old covenant the new covenant is forever. Therefore, Paul says, anyone in Christ is a new creation. The old creature (old Adam) has passed; the new creature has come in the new Adam (Christ). This is not symbolic; it is something vividly real that Christ has done to you and me. Paul calls this ministry of the new covenant the ministry of reconciliation—that in Christ God reconciled us to Himself (5:17-19). As reconciled creatures, therefore, we have become new creations in Christ.