Odin, All Father of the Aesir, is an arbitrary and capricious god. Worshippers offer their sacrifices to him in the hope that he blesses them with health, wealth and, most important, victory in battle. But, despite the integrity of the sacrificer or the purity of the sacrifice, Odin (being an arbitrary and capricious god) may still abandon his followers in the midst of battle. So, then, why worship such a fickle god? Because, to forsake Odin and renounce faith in him, to turn one's back on him, means the All Father will most likely execute his people in some sad and horrible way. All gods invented by men are arbitrary and capricious. How could they not be? They're not real, not alive. And being the projections of men's fear and insecurity, they are as undependable and unpredictable as the emotions of the men who invented them. In fact, what we are really doing when we invent gods and attach a religion to them—religion that is always at base about our attracting the gods' attention, offering sacrifices to earn rewards and avoid punishments, trying to pass the test so we can be granted entry into Valhalla after death—is nothing more than our bargaining with the future for another day on the sunny side of a grave.
Christianity, on the other hand, is the end of religion. That is, specifically, Jesus is the end of all gods and religions invented by men. Jesus reverses everything, contradicts everything taught about the gods and their religions. Jesus reveals that we were not created by gods to be their slaves. We were created by our heavenly Father to receive all things from Him as free gift. We are not put on earth in order that God can test us, and depending on how we do on the test, we either gain an eternal heavenly reward or hellish torment. We are justified, instead, by Jesus' innocent suffering and death on a cross. We don't sacrifice ourselves to God, He sacrifices Himself for us. Worship is not from us to God and His divine "Amen" to our efforts, but God comes to us and serves us, and for this kindness we say "Amen."
Our Lord and God is not an arbitrary and capricious god like Odin. Our God is faithful even when we are faithless, and He will never abandon or forsake us. When Jesus says, "It is finished" we may include in that the all-too-human worship of gods invented by men.
However, this means, too, that when Christianity becomes just another religion it's easy to spot. When Christianity becomes just another old-time religion, then God, we are taught, put us on earth to test us. Our sacrifices earn divine favor (we hope, because we can never be altogether certain until the Last Day when all will be revealed). God's blessing or cursing hangs on our performance, whether or not we please Him. And Jesus serves as an example for us to follow as we attempt to win our way into heaven. When Christianity becomes just another religion it is a grotesque menagerie of human fears and insecurities. It bargains with the future with sacrifices and offerings intended to turn away God's inevitable wrath and judgment toward us recidivist sinners.
When Christianity becomes just another religion Jesus is made to sit on the bench until Judgment Day when He will come in glory to strike down the damnable and reward the truly deserving. Not that there is not a Judgment Day, nor that hell will not be filled with sinners who rejected the free gift of grace and peace won for them by Jesus at Golgotha. Rather, when Christianity follows the tenets of all the other religions, Jesus does not sit and eat with sinners, prostitutes, and tax collectors. He does not come to seek and save the lost. His blood does not cover the sins of the world. Instead, He sits beyond our reach in unapproachable glory, keeping an account of our good and bad works, awaiting the day when His Father looses Him to rain down judgment upon a world gone all to hell.
The uniqueness of Christianity—the thing that ultimately, finally sets it apart from all religions invented by men—is Christ Jesus crucified for the sin of the world. This is the "good news" of the Christian Gospel. Our God became flesh, suffered, died and was buried, descended into hell, and was raised from death on the third day for us. God's Word seeks and saves us. Jesus' bloody sacrifice satisfies God's furious anger over sin. All from Him to us as free gift. Nothing arbitrary or capricious about our God. Just grace and peace in the Name of Christ Jesus, and the faith gifted to us to believe it's all true, all trustworthy, because our God is the man, Jesus Christ, and He is the living God who cannot be contained, confined, or controlled by the fears and insecurities of men. Instead, He sets us free from our fears and insecurities to enjoy and celebrate being the people of God.