Perhaps the most difficult aspect of Christianity to comprehend is the fact that Jesus lives in the heart of every believer. Paul referred to this doctrinal truth as a secret and said;

Now I am full of joy to be suffering for you. In my own body I am doing my share of what has to be done to make Christ’s sufferings complete. This is for His body which is the Church. I became a preacher in His church for your good. In the plan of God I am to preach the Good News. This great secret was hidden to the people of times past, but it is now made known to those who belong to Christ. God wants these great riches of the hidden truth to be made known to the people who are not Jews. The secret is this: Christ in you brings hope of all the great things to come. We preach Christ. We tell every man how he must live. We use wisdom in teaching every man. We do this so every man will be complete in Christ. (Colossians 1:24-28, NLV)

Paul wanted the believers in Colosse to understand that the truth of the gospel was not conveyed to them through natural means, but that God had imparted the wisdom and knowledge of Christ directly to them through his Holy Spirit. Paul described the supernatural process of regeneration in Colossians 2:11-15. He said:

When you became a Christian, you were set free from the sinful things of the world. This was not done by human hands. You were set free from the sins of your old self by what was done in Christ’s body. When you were baptized, you were buried as Christ was buried. When you were raised up in baptism, you were raised as Christ was raised. You were raised to a new life by putting your trust in God. It was God Who raised Jesus from the dead. When you were dead in your sins, you were not set free from the sinful things of the world. But God forgave your sins and gave you new life through Christ. We had broken the Law many ways. Those sins were held against us by the Law. That Law had writings which said we were sinners. But now He has destroyed that writing by nailing it to the cross. God took away the power of the leaders of this world and the powers of darkness. He showed them to the world. The battle was won over them through Christ. (NLV)

Christ’s death on the cross was the final step in God’s effort to reconcile the world to himself. Because the penalty for all our sins was paid by Jesus, we are able to live free from the guilt of sin and escape the penalty of death that we deserve. Through the process of regeneration we have not only been united with Christ, but also with every other believer in the world. Paul said, “And not holding fast to the Head, from whom all the body, nourished and knit together by joints and ligaments, grows with the increase that is from God.” (Colossians 2:19, NKJV).

The Greek word Paul used that is translated knit together in Colossians 2:19 is sumbibazo (soom-bib-ad’-zo) which means “to drive together that is unite (in association or affection)” (G4822). Mentally, sumbibazo infers showing or teaching someone something. The Greek word sumbibazo is derived from the words sun (soon) and basis (bas’-ece). These two words have to do with Jesus’ ministry on earth when he was spending all his time with his disciples teaching them about the kingdom of heaven (G939/G4862). What Paul was saying was that when we become Christians, we enter into the same kind of relationship with Jesus that his disciples had. He is with us all the time, actually dwelling inside us through his Holy Spirit, and he causes us to grow spiritually.