What does the Bible say about vain religion?

Vain religion is depicted in the Scriptures as a practice that appears righteous on the outside but lacks genuine faith and fruitfulness. In Matthew 21, Christ curses the barren fig tree that had leaves but no figs, symbolizing apostate Israel who followed vain traditions rather than the true Gospel. The people were caught in rituals such as the Passover, celebrating without understanding its meaning, which centers on salvation through the blood of Christ. This underscores the danger of a faith that is merely superficial, lacking the substance of true belief and dependence on God's grace.