carefully investigated

When Peter was writing his first epistle, he focused on the truthfulness of the Gospel message and what he called "the word of the prophets made more certain".  The writers of the New Testament depended on the faithful witness of the old.  Peter says it this way:

1Pet. 1:10        Concerning this salvation, the prophets, who prophesied about the grace that would come to you, searched and carefully investigated. 11 They inquired into what time or what circumstances the Spirit of Christ within them was indicating when he testified in advance to the sufferings of Christ and the glories that would follow. 12 It was revealed to them that they were not serving themselves but you. These things have now been announced to you through those who preached the gospel to you by the Holy Spirit sent from heaven--angels long to catch a glimpse of these things.
Praise God!