1 Corinthians 6:9–11 — Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, 10 nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, will inherit the kingdom of God. 11 Such were some of you; but you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus Christ and in the Spirit of our God.
We are following a chain of spiritual consequences that begins when someone is converted, and seeing how these are outwardly represented to us in baptism. We saw that sin makes us filthy but God has provided the only way by which we may be cleansed. We went on to see that this work of cleansing is affected by the Holy Spirit, that it is of necessity a spiritual cleansing and is accompanied by the added blessing that the Spirit Himself takes up residence in the heart of the believer. This time, we want to consider that by virtue of the indwelling of God's Spirit, the believer will be made more and more holy. To put it another way, he or she will be changed more and more into the likeness of Christ.
We already noted that baptism is a mark of God's ownership. As such, it indicates a setting apart (sanctification) to God and from sin - a work performed by the Holy Spirit. God regards the believer as holy because the perfect life of Christ is credited to his or her account. However, the indwelling Spirit also works over time in each believer, influencing their hearts through the various means of grace to form the likeness of Christ in them. They are progressively being renewed, putting off the practices of the old life, in which they were rebels to God and slaves to sin, and putting on the new self. Before the Holy Spirit came to live in their hearts, they were not able to do this, but now they are commanded to do so:
Colossians 3:8–11 — But now you also, put them all aside: anger, wrath, malice, slander, and abusive speech from your mouth. 9 Do not lie to one another, since you laid aside the old self with its evil practices, 10 and have put on the new self who is being renewed to a true knowledge according to the image of the One who created him— 11 a renewal in which there is no distinction between Greek and Jew, circumcised and uncircumcised, barbarian, Scythian, slave and freeman, but Christ is all, and in all.
The "Holy Spirit" is called by that name in part because it is His task to create holiness (Christ-likeness) in God's children. So, when we see someone undergoing baptism, we are to understand that what is represented is that a life newly possessed by the Spirit of God and indwelt by Him will be progressively recreated to bear more and more of the likeness of Jesus Christ. There is no such person as a believer in Christ who is indwelt by the Spirit but is not being fashioned in the likeness of Christ. Those of us who have been baptized might well ask ourselves, therefore, whether we have begun, and are making progress in this process, which our baptism proclaimed as the inevitable experience of every true child of God.