How can I recognize a false conversion?

from the old testament

• The Old Testament doesn't directly address the concept of "false conversion" as it's understood in the New Testament context of personal salvation through Christ. However, it does provide principles and examples that help identify the difference between outward religious behavior and genuine heart transformation. For example, outward worship without heart transformation is meaningless. Through the prophet Isaiah, the Lord said about Israel, “. . . this people draw near with their mouth and honor me with their lips, while their hearts are far from me, and their fear of me is a commandment taught by men” (29:13).
• God values a repentant and humble heart over religious rituals (Psalm 51:17).
• True devotion leads to consistent obedience, not just hearing God’s Word. Ezekiel 33:31-32 rebukes those who listen to God but live as if His words have no authority.
• Hosea 6:4-6 compares Israel’s fleeting devotion to the morning mist and affirms that God desires steadfast love over burnt offerings.
• A false follower may appear religious but lacks true knowledge of God. Jeremiah 9:23-24 contrasts boasting in wisdom, might, or riches with truly knowing and understanding the Lord.

from the new testament

• Conversion is not a product of our will; it is the supernatural act of the Holy Spirit of God (John 1:12-13). He redeems us by the blood of Christ, which was shed on the cross for our sins (Luke 22:20); He indwells us to guide our spiritual growth (1 Corinthians 3:16), and He assures us that we are His (Romans 8:16).
• After that, He seals us and keeps us secure so that true conversions last forever (Ephesians 1:13, 4:30; Jude 1:24). True Christians have been born again (John 3:3) and are controlled by the Holy Spirit; they are no longer controlled by their sinful nature (Romans 8:9).
• In speaking about false prophets, Christ said, "You will recognize them by their fruits. … A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit" (Matthew 7:16, 18).
• True Christians still sin, but they will not repeatedly engage in sinful behavior, understanding that "no one born of God makes a practice of sinning, for God's seed [nature] abides in him, and he cannot keep on sinning because he has been born of God" (1 John 3:9).
• A true convert is one whose conversion is eternal. He does not fall away because of persecution or trials. In fact, trials increase the faith of the true believer, strengthening him and proving that his faith is real (1 Peter 1:6-7).
• The parable of the sower in Matthew 13 describes the kind of false converts who "when tribulation or persecution arises on account of the word, immediately he falls away" (v. 21). False converts are also turned away from the faith by "the cares of the world and the deceitfulness of riches" (v. 22), which choke the Word of God out of their lives and make it unfruitful. The Word always produces fruit in the life of the true believer.

implications for today

Sinful behaviors and desires diminish in the true convert; the desire for righteousness and holiness becomes the hallmark of a truly converted life. The things of this world have less influence on the truly converted as they mature in Christ (1 John 2:16). The desire to live for ourselves decreases as our desire to live for the One who died for us increases. The Holy Spirit in us produces His fruit and the evidence of that fruit becomes more obvious (Galatians 5:22-23).

This is the key to identifying false conversions. The fruit of a true conversion is evident in the converted person. Truly converted sinners have trusted Christ alone and are being made more Christlike all the time. Those who claim to be Christians should display the characteristics of true Christians: sound doctrine, obedience to God's Word, and love. The things of the world hold less attraction for them. But false converts are increasingly attracted to the world and all it offers. Jesus said that we can do nothing apart from Him, and a true convert remains in Him so that His fruit is produced in us. He is the Vine; we are the branches. It is His fruit produced in us that remains as we remain in Him (John 15:1-6).

Detecting a false conversion isn't always easy, and the cause for false conversions vary. Sometimes the false convert may not even realize it; other times a person falsely converts to intentionally deceive. It is not a Christian's place to judge the salvation of another person, though we are called to be discerning. While false Christians may sometimes be able to deceive us, they will never deceive God, because "no creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account" (Hebrews 4:13). We should continue to seek God's truth and to share it with others.