Christian prophets mentioned in the Old Testament include Isaiah, Ezekiel and Daniel. Prophets who appear in the New Testament include John the Baptist, Jesus Christ, Peter and Judas Iscariot. Christians consider a prophet to be a person who God chooses through the Holy Spirit to deliver a message for a specific purpose.
Prophets in the Bible speak about future events and God's plan, exhorting people to obey. Prophets in the Old Testament acted as preachers and also admonished people for their sins.
The Book of Isaiah contains a prophecy of Jesus Christ's birth. Isaiah opposed Judea's forming alliances with other countries, but God told Isaiah that nobody would listen to him, as people trusted mankind more than God. Ezekiel was forced to live in exile in Babylon, during which time God called him as a prophet. He prophesied that God would cause Jerusalem to fall as punishment for people's apostasy. Daniel's prophecy involves God's plan for the Jews and Israel following Gentile domination.
In the New Testament, Jesus mentions several times that his words are coming from God, rather than himself. Along with prophets, the evangelists and the apostles were leaders in the early Christian church. Corinthians mentions that prophets speak to people to encourage and console them.