What does the Bible say about self-deception?

Bible Topic · WEB

The Bible warns that self-deception occurs when people mistake outward religion, religious knowledge, or good intentions for genuine faith that produces obedience and love. James 1:26 teaches that a person who considers himself religious but does not control his tongue deceives his own heart, and his religion is worthless. True faith is not sinless perfection, but it humbly receives God's Word, repents of sin, and bears fruit by the Spirit. Scripture therefore calls believers to examine themselves honestly before God, trusting not their own appearance of godliness but Christ alone, whose grace transforms those He saves.