In his rebuke of the "foolish Galatians," Paul asks the question "Who has bewitched you? It was before your eyes that Jesus Christ was publicly portrayed as crucified." Because there is so much going on in Galatians this little gem of a verse is often overlooked. But notice what Paul is saying--he is claiming that the Galatians "saw" Jesus Christ crucified in his preaching of the gospel. These Gentiles lived hundreds of miles from where Jesus ministered and several decades later; as such they never physically saw Jesus with their physical eyes. But in the preaching of Christ crucufued Paul claims that the Galatians "saw" Jesus publicly portrayed as crucified.
In my estimation this is one of the great descriptions of gospel preaching--preaching in such a way that those who hear the message "see" Jesus Christ as the crucified one. That they see Jesus as the one crucified for their sins. For it is in this seeing of Jesus that we are transformed into his image (2 Cor 3:18). This, then, is the great task of preaching.