Definitions of the following words:
1. Kerussein: The most common word, which the New Testament uses to describe the act of passing along God’s thoughts on salvation, is kerussein, to preach. Originally, this word depicts the acts of a herald who, on behalf of his king, publicly presents to the people the words of their lord. The act of preaching is kerugma; the preacher is a kerux.
2. Euangelizein: to give a good message. If kerussein focuses on the formal act of preaching, euangelizein has to do with the content of the message.
3. Didaskein: to teach. This euangelion, this evangel, good news, is also instruction.
4. Didache: The didache, on the other hand, is ethical instruction, as exemplified in the Didache ton Dodeka Apostolon, which was directed to those who had been converted to the Christian Faith
5. Marturein: to witness. The basic meaning is one that gives confirmation that a certain fact is true.
6. Kerygma: in Christian theology, respectively, the initial proclamation of the gospel message and the oral instruction given before baptism to those who have accepted the message. Kerygma refers primarily to the preaching of the Apostles as recorded in the New Testament. Their message was that Jesus Christ, in fulfilment of the prophecies of the Old Testament, was sent by God, preached the coming of the Kingdom of God, died, was buried, rose from the dead, and was raised to the right hand of God in heaven. To those who accepted this proclamation, the reward was deliverance from sin, or salvation. Acceptance into the church required conversion—that is, a turning away from a life of sin. Early Christian catechesis was concerned primarily with exhorting those preparing for baptism to follow the way of “life” as opposed to that of “death”; it was distinguished from the more doctrinal instruction that followed one’s baptism. Kerygma, e.g., in 1 Cor. 1:21, is that which the Christian preacher preached in order to save people.