Christianity is an irreligious religion, because Christianity is not about religious observances or other human activities, but the giftedness through which God gives Himself to sinful humans and redeems them from sin and death. A religion that is defined by human activity is not a true religion.  Human self-centeredness gives birth to this religious fiction. Humans are always dreaming they can do something to propitiate God's wrath: "Hey God, see what I have done for you! Aren't you happy with me now?" Uh, not really. The god who is satisfied by our paltry efforts is not a god at all, but a fiction. A religious fiction has only a fictional god. A false belief gives rise to a false god, the idol of our pious imagination. Such a false piety must be repented to death, so that God can be God for us.

True piety gives up confidence in human efforts, works, and observances. True piety trusts in God's own Son, who was given up to death for us sinners. Here is the work which abides forever, the perfect work of the eternal Son of the Father, who was crucified to give us life and peace. What other piety, what other work, observance, or religious hoop jumping would even begin to compare to the work of God's Son?

What blind madness we humans exhibit trying to pawn off on God our own works as a substitute for the work of the perfect Substitute for sinners! Those who want to help God out with their self-generated works have made themselves their own wretched idol and called into question the ability of God's Son to save those He has promised to save. If we can create a do-it-yourself religion, then Christ died for nothing.