Kerygma is a Greek word which means "proclamation, announcement, preaching" (BAGD, 430-31). In Erasmian Greek pronunciation, which is used in most universities for ancient Greek, both biblical and classical, kerygma is pronounced "kay-roog-ma" where the first "a" is long and the last "a" is short. Related words are kerux ("herald, preacher" (BAGD, 431) and kerusso ("announce, make known, proclaim aloud, preach" (BAGD, 431).
Because of the influence of the British scholar C. H. Dodd and others, kerygma has become a technical term in biblical scholarship with a special meaning. Dodd attempted to decipher the significant heart and soul of early Christian preaching by examining the sermons in the book of Acts and certain other significant NT texts which appeared to contain the preaching thrust of the early church in a nutshell (The Apostolic Preaching, 1936). Kerygma is distinguished from didache, the latter referring to "doctrine" or "teaching." Kerygma means the initial gospel proclamation designed to introduce a person to Christ and to appeal for conversion. Didache refers to the doctrinal and ethical teaching of the church into which a person needs to be grounded once they become a Christian. Of course, there is overlap in the use of these terms just as there is overlap in actual Christian practice. For example, the kerygma includes the preaching of the cross as a central element. That does not mean that the preaching of the cross does not also have a central place within didache.
The ancient kerygma as summarized by Dodd from Peter's speeches in Acts was:
1. The Age of Fulfillment has dawned, the "latter days" foretold by the prophets.
2. This has taken place through the birth, life, ministry, death and resurrection of Jesus Christ.
3. By virtue of the resurrection Jesus has been exalted at the right hand of God as Messianic head of the new Israel.
4. The Holy Spirit in the church is the sign of Christ's present power and glory.
5. The Messianic Age will reach its consummation in the return of Christ.
6. A appeal is made for repentance with the offer of forgiveness, the Holy Spirit, and salvation.
Christ, of course, was the center of this ancient kerygma. The cross and resurrection are crucial to the kerygmatic preaching of Christ.