How should Christians respond to someone who leaves the faith?The idea of someone leaving the faith is almost impossible for us to grasp. How can someone experience the goodness of God, the love of Christ, and the peace which surpasses all understanding (Philippians 4:7) and turn away from it? In one of his epistles, the apostle John wrote; "They went out from us, but they were not of us; for if they had been of us, they would have continued with us. But they went out, that it might become plain that they all are not of us" (1 John 2:19). In other words, John is saying that those who truly depart from the faith were never really walking in the faith.
This may be true of many people; indeed, Jesus tells a terrifying truth in Matthew 7. He says, "Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. On that day many will say to me, 'Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?' And then will I declare to them, 'I never knew you; depart from me, you workers of lawlessness'" (Matthew 7:21–23). They might outwardly appear righteous, claim Jesus' name, and even have an effective ministry. But there has been no inner heart change; they do not actually know Jesus and He does not know them.
There are also those who profess to be Christians, but their lives do not bear the fruit of repentance (Matthew 3:8; Luke 3:8; Acts 26:20; Galatians 5:22–23; James 2:18–26; 1 John 4:13–21). These might be people who identify themselves as "Christian" but their lives do not line up with the truths they profess. It seems likely that many of these will depart from the faith before the end of their life. They will come to realize they do not believe what they have professed, or they will become uncomfortable with parts of Christian belief. This is less of a departure and more of a realization that they did not have the faith they thought. These are probably the most common individuals who "leave the faith" that we will encounter.
However, there are those who are truly of the faith, but for one reason or another, they become enchanted with the world, or deceived into thinking there is something better, or deceived into thinking they have been deceived. Our first instinct is to lean on 1 John 2:19; we assume that they were never of the faith to begin with. However, we should be leaning on Colossians 3:12–14. We should "put on love." In love, we will bear with one another, being patient, kind, humble, and forgiving. We'll also share truth (Ephesians 4:15). Jude 1:22–23 counsels, "And have mercy on those who doubt; save others by snatching them out of the fire; to others show mercy with fear, hating even the garment stained by the flesh." Similarly, 1 Thessalonians 5:14 says, "And we urge you, brothers, admonish the idle, encourage the fainthearted, help the weak, be patient with them all."
When we personally encounter those who are experiencing doubts about their faith or otherwise seem to be wandering away, we can pray for them. We can also help them to see and understand the truth about God. We can help them find answers to their questions. We can warn them about sinful lifestyles. We can demonstrate love to them by continuing to walk alongside them. We portray the realities about God both in what we say and in what we do. It is important not only to know and speak truth, but to live it (James 1:22).
It might be helpful here to review some basics about salvation. First, we must recognize that we are incapable of saving anyone, including ourselves. Scripture is clear: salvation is the work of God through Christ Jesus (John 3:16–18; Ephesians 2:1–10; 1 Peter 1:3–9; Titus 3:3–7). Apart from God, all of us are spiritually dead. We are made spiritually alive only because of Jesus and by God's grace through faith. We can take no credit for our own salvation. Knowing our prior position and the astounding reality of life in Christ, we share the truth of the gospel with joy and humility.
Though we are tasked with sharing this message of hope and redemption, we don't actually save anyone; again, that is God's work alone (John 6:44). After we are saved, we begin the process of sanctification, by which we come to know God more and through which He transforms us to be more like Jesus (Romans 8:28–30). We participate in this work, but it is, again, ultimately something God does (Philippians 1:6; 2:12–13). So when we personally encounter those who have left the faith or are considering leaving the faith, whether unbelievers who formerly professed Christianity or true believers in a time of struggle, we first bring them to God in prayer. He will be the one to change their hearts. He will also be the one to give us wisdom in how to best interact (James 1:5). We share His truth and continue to love these people.
We must also recognize that no one who is truly saved can become unsaved. Jesus said, "My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father's hand. I and the Father are one" (John 10:27–30). It is impossible for a Christian to lose their salvation. So, while there may be those who are truly saved, but for a time, turn away from their faith, they are still firmly in the grasp of Jesus Christ. This only serves to reiterate the truths of Galatians 6:1–5, Colossians 3:12–14, 1 Thessalonians 5:14, and Jude 1:22–23. Our desire is that these people grow in Christ (Ephesians 1:15–23; Colossians 1:9–14), and a lack of love in action will only prolong their time away.
In short, a true Christian never really leaves the faith, but like all sinful creatures, we are prone to wander at times. Our reaction to those who are struggling in their faith should be to love them just as Christ has loved us. If they truly leave the faith, never to return, then they were never really in the faith.
As a final thought, it is impossible for anyone to know for certain if anyone else is saved. We may have a good idea, and there are ample indicators of someone being truly saved (for example, Galatians 5:22–23; 1 John 3:4–10, 19–24; 4:13–21). However, it is God who knows the heart (Jeremiah 17:10). So, while we can have a pretty good idea of whether or not a person is saved, we do not truly know their heart; only God does. Therefore, we must turn to Him as in all things, asking for His grace and peace to be upon all those who profess to belong to Him, asking Him to convict our hearts and minds to repentance and redemption; and we must "keep loving one another earnestly, since love covers a multitude of sins" (1 Peter 4:8).
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