The Gospel: the power of God unto salvation to everyone that believeth

All have sinned and come short of the glory of God. Romans 3:23. In fact in Romans 3:9-20 the Apostle Paul gives a very negative view of each and every one of us. He says there is none righteous, none that does good, unprofitable, none that understands, liars, and destruction and misery are in our ways.

All the world is guilty before God (Romans 3:19). It is God’s law that declares each and every one of us as guilty before him, and therefore as Paul declares, by the deeds of the law there shall no flesh be justified in his sight. The word "justified" means to be found free of guilt, (just as if I had never sinned). The law cannot justify us because it’s the very thing that declares our guilt.

God is a just and righteous judge. God must be legally and morally right in all that he does. His righteousness and justice will not allow Him to justify a guilty man, therefore the dilemma is how can God justify the guilty and he himself remain just?

God’s righteousness without the law has been revealed (Romans 3:21). And this righteousness is revealed in the gospel of Christ (Romans 1:16-17). This gospel is defined in 1 Corinthians 15:1-4, as "how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures". And this gospel now declares God's righteousness, "that he might be JUST and the JUSTIFIER of him which BELIEVETH in Jesus" (Romans 3:26).

Therefore, God's Son, the Lord Jesus Christ, took our guilt upon himself and died under our own condemnation to appease the justice and righteousness of God (Romans 3:25), and now God will FREELY justify any man (Romans 3:24) who simply believes the gospel of the death, burial, and resurrection of Christ, and puts all their trust in the finished work of the cross (Ephesians 1:13; Ephesians 2:8-9).

What must I do to be saved? Believe on the Lord Jesus Christ, and thou shalt be saved (Acts 16:30-31). Religion tells you to do something. God says his Son did it all, therefore, only believe on him.