What true religion is not: It is not observing a list of rules or rituals.
“When you come to appear before me, who has required of you this trampling of my courts? Bring no more vain offerings; incense is an abomination to me. New moon and Sabbath and the calling of convocations — I cannot endure iniquity and solemn assembly. Your new moons and your appointed feasts my soul hates; they have become a burden to me; I am weary of bearing them. When you spread out your hands, I will hide my eyes from you; even though you make many prayers, I will not listen; your hands are full of blood. Wash yourselves; make yourselves clean; remove the evil of your deeds from before my eyes; cease to do evil, learn to do good; seek justice, correct oppression; bring justice to the fatherless, plead the widow’s cause.” (Isaiah 1:12-17)
Believing we can please God and be right with God by observing certain ordinances or following a list of man made rules places ourselves, not God, at the center of our theology. True religion is not rules or rituals based. It is a relationship with a Holy and Righteous God. True religion is recognizing that we are separated from God by what we do and only God Himself can rectify that separation because only God can satisfy the wrath of God. Only God can pay the price that our sin demands.
True religion can and does incorporate rules and rituals. But we observe these rules and rituals not to earn salvation but as a demonstration of our gratitude for the salvation God has so graciously provided. They are not an effort to be right with God but are a manifestation of our right relationship with God. Therefore, “If anyone thinks he is religious and does not bridle his tongue but deceives his heart, this person’s religion is worthless. Religion that is pure and undefiled before God, the Father, is this: to visit orphans and widows in their affliction, and to keep oneself unstained from the world.” (James 1:26-27)