Galatians 2.16 observes, and yet because we know that a person is not justified by the works of the law but by faith in Jesus Christ, even we ourselves have believed in Christ Jesus. This was so that we might be justified by faith in Christ and not by the works of the law, because by the works of the law no human being will be justified.
We are justified before God, that is, we are made right before God, so that we will not be condemned by God, by faith and not by works. How are we justified by faith? Our faith is in the work of Christ, the life of Christ, being both sufficient to satisfy the justice of God and appropriated to us, as our own, by God’s grace and mercy, granted to us through repentance and belief in Him.
What must we believe? We must believe that Jesus lived among us as a Man while still being God, that He came to earth and lived perfectly as men must before God, that He was crucified on the cross as punishment for the sins of men and that He was raised from the dead proving He is both the giver of eternal life and able to appropriate to all those He chooses, His works of righteousness as well as His pardon for sin.
God is love so He sent His Son to be our Savior. God is just so He sacrificed His Son for our sins. God is love so He raised Himself from the dead and gives life to all those who humble themselves before Him and cry out for mercy. God is just and will condemn to hell forever all those who reject Him and His work in His Son.
We are made right with God by receiving His pardon for our disobedience not by attempting to please God through doing our own good works for they will not make us perfect and they do not negate the failure to do all that God requires all the time.
It is these truths that separate Christianity from all other religions and make the Christian about a relationship and not about a religion.