Concerning this salvation, the prophets sought and searched diligently, who prophesied of the grace that would come to you,
The title "Spirit of Christ" occurs elsewhere in the New Testament only in Romans 8:9. In both places it probably signifies not only that the Spirit came from Christ but also that He witnesses to Christ as His representative (cf. John 15:26-27). Peter was stressing the Spirit’s witness to Christ in the Old Testament rather than the preexistence of Christ. [Note: Davids, p. 62.] 