There are many differences between the three main branches of Christianity (Roman Catholicism, Eastern Orthodoxy and the various types of Protestants). However, as streams within the overall Christian tradition, they are akin in certain basic beliefs. These primary tenets of faith include:
The Bible is inspired and authoritative.
God exists as the eternal Trinity.
Creation: The Cosmos was created in a state of completion, but is now fallen into a state of futility due to sin.
Human Nature: People are specially made in God’s image, but are fallen through sin into separation from God and the degeneration caused by sin.
Jesus Christ is the Messiah of Israel and the Son of God. He is the Second Person of the eternal Trinity. Jesus is both fully God and fully man.
The Atonement: Jesus’ death paid the penalty for human sin and opened the way to restore people to God. His resurrection validates the Father’s acceptance of his atonement.
Human Response: Faith toward God (specifically in Jesus) is what God requires for people to receive forgiveness and new life. Faith is a deep level of trusting, which results in actions which show its reality.
The Church: All who have faith in Christ are part of the Body of Christ, which is manifested in local bodies of believers, known as churches.
Holy Living: Faith shows itself in new desires which, honor God accompanied by a new power for living. The old sinful desires and tendencies can still operate, but no longer have complete control.
Death and Eternity: Death is the natural result of being separated from the Living God. Eternity follows physical death and seals a person in a state of faith or unbelief. Eternal life or eternal condemnation await everyone.
The Future: The present age will end with a catastrophic clash between the Kingdom of God and the world-system. Jesus will return to rule. The Cosmos will be remade to exclude evil.