What does the Bible say about true and false religion?

In Galatians, Paul draws a clear distinction between true and false religion. True religion is characterized by a genuine faith in Jesus Christ and His finished work, while false religion often focuses on outward rituals, legalism, and self-righteousness. As Paul warns, those who glory in their fleshly achievements misinterpret the essence of faith, seeking approval from men rather than God. Therefore, true believers are to boast only in the cross of Jesus Christ, as true faith is rooted in reliance on His grace and mercy, not personal merit or achievements.