For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
James Kraft
Romans 1:16. For I am not ashamed of the gospel of Christ, First Corinthians 15:3-4, For it is the POWER of God unto salvation to everyone that BELIEVETH, to the Jew first, and also to the Greek.
Acts 16:31 Believe on the Lord Jesus Christ and thou shalt be saved and thy house.
Paul preached the good news of the gospel. That Christ died for our sins and rose again for our justification.
Galatians 1:6-9 Though we or an angel from heaven preach any other gospel unto you than that we have preached unto you, let him be accursed. As we said before, so say I again, if any man preach any other gospel unto you than that ye have received from us, let him be accursed.
Paul preached the gospel of salvation by grace apart from any works for the free gift of eternal life.
He preached the seal of the Holy Spirit was given us the second we believe on Jesus for the free gift of everlasting life.
Romans 3:26-28 For He is the just and the justifier of them that BELIEVE of their own free will on Jesus finished work on the cross plus nothing.
Where is boasting then? It is excluded. By what law, by the law of works? Nay, but by the law of FAITH. Therefore we conclude a man is justified by FAITH apart from the deeds of the law. For by the deeds of the law shall no flesh be justified.
The GIFT of God is eternal life. Not a reward for good behavior, but a free gift.