You can tell a lot about people from the clothes they wear. The clothes that we choose to wear often reflect our status, our values, and even our priorities. At Hollywood red carpet events reporters often ask actors and actresses "Who are you wearing?" to find out which designer created the clothes they are wearing. In the ancient world clothing had a similar significance. It could reflect a person's socioeconomic status, mood, or even their character.
The New Testament uses clothing imagery to describe three different, but closely related, aspects of our relationship with God.1 First, it emphasizes our union with Christ that happens at our conversion. In Galatians 3:26-27 Paul writes that "in Christ Jesus you are all sons of God, through faith. For as many of you as were baptized into Christ have put on Christ." Therefore everyone who has committed their life to Christ by faith has the status of having "put on Christ."
Second, clothing imagery vividly portrays the transformation that results from our relationship with Jesus Christ. In contrast to living a life of disobedience to God and his ways (Rom 13:13), Paul instructs believers to "put on the Lord Jesus Christ, and make no provision for the flesh, to gratify its desires" (Rom 13:14). Sometimes the command is to "put on" certain godly characteristics that are a reflection of Christ himself: "Put on then, as God's chosen ones, holy and beloved, compassionate hearts, kindness, humility, meekness, and patience" (Col 3:12). Thus the call to "put on" these godly characteristics is rooted in our status as those who are holy, chosen and loved by God.
Third, clothing imagery describes the transformation of our bodies that will take place when we are resurrected from the dead. Paul explains that "this perishable body must put on the imperishable, and this mortal body must put on immortality" (1 Cor 15:53). In the meantime, as we await that day, "we groan, longing to put on our heavenly dwelling, if indeed by putting it on we may not be found naked. For while we are still in this tent, we groan, being burdened—not that we would be unclothed, but that we would be further clothed, so that what is mortal may be swallowed up by life" (2 Cor 5:2-4).
Thus, in summary, every believer has put on Christ by virtue of trusting in who Jesus is and what he has done for us. Yet we are also called to put on the character qualities and virtues that reflect our identity as children of God. We pursue this lofty goal in anticipation of the day when we will take off our mortal bodies and put on resurrected bodies that fully reflect Christ's own resurrection body.
1. I am indebted to the helpful material found in Constantine R. Campbell, Paul and Union with Christ: An Exegetical and Theological Study (Grand Rapids: Zondervan, 2012), 310-23.