The basic principle of Christianity is faith in Jesus, the son of God and the Messiah (Christ). Jesus was born in Bethlehem, Israel (Palestine). Christians believe that Jesus Christ was born to preach the gospel, the good news of God, and teach people. The key belief is faith in the crucifixion of Jesus, which represents the atonement for all human sins and his resurrection from the dead. Christians celebrate Jesus' birthday as Christmas, and the day of His resurrection from the dead as Easter. The day of the crucifixion of Christ is celebrated as Good Friday. Christians believe in a general resurrection of the dead and a new life.
The year of Jesus' birth represents the year of the beginning of a new era and a new way of counting time. Jesus Christ, the Son of God, spreads his teaching of salvation from death among people in order to ultimately sacrifice himself to humanity through martyrdom, rise from the dead and rise again and ascend to heaven.
Recent research confirms that Jesus existed (works by non-Christian writers of the first century - Josephus and Tacitus). The main source of the life and work of Jesus Christ is the New Testament, the second part of the Holy Christian Book, the Bible (the Greek Bible is translated as "Book") or Scripture.