Rom 1:14 I am debtor both to the Greeks, and to the Barbarians; both to the wise, and to the unwise.
Rom 1:15 So, as much as in me is, I am ready to preach the gospel to you that are at Rome also.
Rom 1:16 For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek.
--Paul was a debtor. He owed it to the unsaved at Rome. He preached the gospel to the unregenerate at Rome. He went to the Jew first and then to the Gentiles. The gospel is the power of God unto salvation.
It alone can save.
1Co 1:17 For Christ sent me not to baptize, but to preach the gospel: not with wisdom of words, lest the cross of Christ should be made of none effect.
--Paul was not sent to baptize, not to the Christians, but rather to preach to the unsaved, to take the gospel to those who have not heard it. Things like baptism were left up to other pastors.
1Co 1:18 For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God.
--Those that are perishing are the unregenerate. Paul went to the unregenerate with the gospel. They were the foolish ones on their way to hell. They needed to be saved; born again. He had a heart for the lost, just as God did.
1Co 1:21 For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe.
What is the pleasure of God SBM? The pleasure of God is that by the preaching of the gospel the unregenerate will save. And who will be saved? Those that believe will be regenerated and saved.
Paul preaches the wisdom of God, the foolishness of preaching to these unregenerate people that they will be saved.
It can't get any clearer than that, can it?