What agreement has the temple of God with idols? For we are the temple of the living God; as God said,
“I will make my dwelling among them and walk among them, and I will be their God, and they shall be my people. Therefore go out from their midst, and be separate from them, says the Lord, and touch no unclean thing; then I will welcome you, and I will be a father to you, and you shall be sons and daughters to me, says the Lord Almighty.”
Since we have these promises, beloved, let us cleanse ourselves from every defilement of body and spirit, bringing holiness to completion in the fear of God.
When God was teaching the nation of Israel how to be a country and a people and a religion, it was very important that they not mix any of their new nation or new religion with the people they were displacing. After 400 years of living in slavery to the Egyptians, they had a LOT of things to unlearn.
Paul quotes this event in his letter to the Corinthians, because they are in the same situation. Many of them have lived in the wicked city of Corinth for their entire lives and desire to grow in Jesus. While they are running towards growth and life in Jesus, they are carrying a bunch of baggage from their lives as idol worshipers and evil doers.
When I first became a Christian, I sat down with a buddy and trashed all of my CDs. I had some pretty filthy stuff, and I knew that it wouldn’t help me grow in the Lord. Without any influence from anybody else, I sat down and started scratching and then throwing away my collection. My buddy caught me and went and got his. We cleaned house! (And thanks to Columbia House, the value of that collection was about $30 after I got 12 for 1¢.)
Even though there is a chapter break in this section, read it all together. Now that our sins are forgiven and we are in Christ, we aren’t coming out and being separate from the world so that God will be close to us, but because God is already close to us. We bring our holiness — already done and accomplished — into completion and fullness by putting off our old wicked ways. It is because God is walking among us that we put off our wicked practices, not to attract Him.
So being separate looks different after Christ has saved us from our sins, but the idea is the same. Jesus said we would be “In the world but not of the world.” We are foreigners wherever we go. But our culture and our lifestyles are always open for review. As outsiders look upon us, our life and practice of our faith in Christ is pure and desirable.
Since we have these promises (past tense! Already in effect!), let us cleanse ourselves and grow in the Lord. He loves it when we draw near to Him and the people around us are looking for signs of life.