How does someone become a Christian? In the next section of this letter, Paul gives two answers to this question. The first is: because of what God has done (vv. 21-23). Having just told us who Jesus is (vv. 15-20), Paul now reminds us how we came to know this Jesus.

In these few verses we have the most amazing summary of the gospel and, indeed, the most compact summary of the whole Christian life. It can be summed up in three very simple words: once . . . but . . . if.

″Once you were alienated″ (v. 21). Paul sums up the entire unbelieving world in these words. They are essentially aliens, and it is a relational alienation due to sin. And like all people, we wilfully chose to cut ourselves off from God before we were Christians.

″But now he has reconciled you″ (v. 22). Enemies are now friends, aliens are now family, all because of Christ's death on the cross. Jesus' death does not just bring us back to God; it also has a future focus-that He might present us holy in His sight, without blemish, free from accusation. The image here is of Judgement Day, when the bride of Christ is presented to her husband. The question is: are you worthy to enter the kingdom? The psalmist says, only the one with clean hands and a pure heart can ascend His holy hill (Psalm 24:4). The good news is that you can confidently reply, ″Yes, I am worthy.″ On that day we will not fear any voice challenging our claim, because Jesus has died for us to make us worthy.

″If you continue in your faith″ (v. 23). Of course, our salvation is secure, but we must continue in this gospel. We have been reconciled to God, and we must not go back to being His enemy. His death has made us holy, so we do not deliberately or wilfully give ourselves to a life of ungodliness.

This is our spiritual biography: once . . . but . . . if.