Simply because it is the Truth. Jesus said this world will pass away but my word will not. Lies come and go but the Truth lasts forever.
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Christianity. Christianity is centered around the life and death of Jesus of Nazareth
The teachings of Jesus ARE Christ's message because he was Jesus Christ. Christ and Jesus are the same person.
I do not think that there are any that are not Christ centered. No matter what is taught Christ and His teachings are there.
Jesus sent his disciples out to spread his teachings to all nations.
The Bible is where the written teachings of Jesus are kept.
Yes, as interpreted by his Disciples. It is also based on the teachings of the Hebrew religion as it existed at the time of Caesar Augustus and Jesus.
Jesus and his teachings are primarily found in the 4 Gospels in the New Testament: Matthew, Mark, Luke & John and in Revelation. Jesus and his teachings are used as a basis for the writings of the remainder of the New Testament.
The teachings that came from religion and not the Bible.
Jesus taught people many things, all which tie back to the central themes of spirituality, his Father Jehovah God's kingdom and love. For example, 1 of the first things he taught the crowds when giving the Sermon on the Mount was that those that are truly happy are conscious of their spiritual need. (Matthew 5:3) He told them to make the interests of Jehovah's kingdom the top priority in their lives for true success. (Matthew 6:33) Jesus told his followers that 1 of the main characteristics that they must have was showing love to one another. (John 13:35) He also taught details of how "the last days" (a.k.a. our times) would be. (Matthew 24:4-25) He let his followers know that it was only through means of his sacrifice (which Jehovah had sent him to Earth for) that people would be able to have eternal life in the future. (John 3:16) (New World Translation of the Holy Scriptures)
True Teachings of Jesus Christ
The teachings of Jesus Christ, hence the name.