19 My brothers and sisters, if one of you should wander from the truth and someone should bring that person back, 20 remember this: Whoever turns a sinner from the error of their way will save them from death and cover over a multitude of sins.
We have different words for somebody who has fallen away from the faith, "backslider", "lukewarm Christian", or "not walking with The Lord". The bottom line is that a lot of us have had times in our lives where we have wandered away from the Truth. Sometimes more obviously and dramatically, or sometimes in the form of the "the subtle sellout". As the passage says we have wandered away from the Truth. We have wandered away from Jesus who is the Truth. And we have believed the lie, the evil one is always throwing in our face.
And what is this lie? The big lie is that we can have a better, easier way outside of Jesus' plan for our lives. Following Jesus is not the best alternative. So we wander away and try out some other way, some other purported "truth". Notice in the NIV translation Truth is capitalized. Showing that it is THE TRUTH! The truth about who God is, the truth about who we are, and the truth about how we in our sinful nature have been reconciled to God through what Jesus did. When someone believes in these truths, they are saved and become children of God. (This is also called "being born again"). As we are saved by the Truth, we continue to walk in it. Since we are given the Holy Spirit, which is also called the Spirit of truth, we now know the difference between right and wrong. As we are guided by the Holy Spirit, we walk in truth, and the truth sets us free.
But despite knowing all of this and having the proof of the Holy Spirit living inside of us, we are still prone to wander. Why? Because we still live with a sinful nature that tells us there is a better way. This nature wants us to take back control of our lives. And when we do this, we wander away from the truth and see the errors of our ways. Here is where being in a community of other believer really helps. When someone knows you it is apparent when one is "straying". Of course God is the only one who can help us turn back to him (this is what the term repent means). But God uses us as brothers and sisters in Christ to bring each other back when we have strayed.
Do you know someone who is wandering away from the Truth? First, all of pray for them that the Holy Spirit in them might guide them back to the truth. Second of all, be part of bringing this person back to God as the Spirit leads you. And know this, when a sinner turns back to God it covers a multitude of sins. How? It covers all the things this person would have done had they not returned to God! We probably cannot imagine what has been prevented as a wanderer finds his way home. In the Prodigal Son story the Father waits for the lost Son and says when he sees him returning, "my son was lost and now He is found!" There is great joy in heaven when one person who is lost is found.