“For I am not ashamed of the gospel of Christ, for it is the power of God to salvation for everyone who believes, for the Jew first and also for the Greek.” (Romans 1:16)
“But why does Paul stress the fact that he is not ‘ashamed’ to bring that gospel to the Roman patricians? The reason is that the apostolic ‘word’ of preaching is closely linked to the cross: ‘For Christ did not send me to baptize but to preach the gospel, and not with eloquent wisdom, lest the cross of Christ be emptied of its power. For the word, namely (the word) of the cross, is folly to those who are perishing, but to us who are being saved it is the power of God.’ (1 Cor. 1:17-18) For Paul, the cross is a reason for boasting: ‘But far be it from me to glory except in the cross of our Lord Jesus Christ, by which the world has been crucified to me, and I to the world.’ (Gal. 6:14) The clue to making sense out of this factual equation between ‘gospel’ and ‘cross’ lies in the aspect of shameful death linked to the cross in the Roman empire.
Crucifixion was intended for public humiliation and was the punishment administered to slaves, foreigners, and those involved in a revolt against the legal authority. It was the opposite of the soldier’s glorious death for the sake of a noble cause: martyrdom for one’s own country or nation or empire. Crucifixion was a death unto total oblivion of someone whose life was unworthy of remembrance: an unworthy end of an unworthy life, shame ending in shame. So Paul here is making sure that his Roman patrician hearers not be mistaken that, should they fully endorse his preaching, they will be considered as having committed the sin of lèse majestè against the emperor and might end up in the arena of the Coliseum.” (Paul Nadim Tarazi, The Chrysostom Bible: Romans, pp 46-47)