Note: Slightly modified from the original articulation (this is not my articulation of the gospel and some of its necessary implications. It is quite solid and sound).
The gospel is the good news of God’s promise to save His people conditioned on the atoning blood and imputed righteousness of Jesus Christ ALONE. In the gospel, the righteousness of God is revealed (Romans 1:16-17, 3:9-26, 4:6-8). A revelation of how God remains JUST to JUSTIFY the ungodly; how God is both a JUST God AND a SAVIOR (Isaiah 45:21; 2 Corinthians 5:21). Anyone who believes that any part of salvation is conditioned on the sinner is lost, including anyone who believes that the work of Jesus Christ alone does not make the only difference between salvation and damnation. Those who do not believe the gospel are lost (Mark 16:16). Those who are ignorant of the righteousness of God revealed in the gospel are lost (Romans 10:1-4). This is NOT saying that believing the true gospel is a prerequisite to salvation; it is saying that when God regenerates someone, He glorifies Himself by causing that person to believe the true gospel of salvation based on the atoning blood and imputed righteousness of Christ. There are not many paths to God; there is only one. And if anyone preaches another gospel, let him be accursed (Galatians 1:8-9). If anyone does not abide in the doctrine of Christ, he does not have God (2 John 9). If anyone will speak peace to one who believes a false gospel, then he, too, is evil (2 John 11). God is glorified in the salvation of sinners when He manifests all His redemptive glory to their hearts (2 Corinthians 4:3-6). He will not have His saved ones spit in the face of His Son and dishonor His redemptive glory (Isaiah 42:6-8).
“And they shall no longer each man teach his neighbor, and each man his brother, saying, Know Jehovah. For they shall all know Me, from the least of them even to the greatest of them, declares Jehovah. For I will forgive their iniquity, and I will remember their sins no more” (Jeremiah 31:34).
“… and all your sons [will be] taught of Jehovah; and the peace of your sons [will be] great” (Isaiah 54:13).
“It has been written in the Prophets, They shall all be taught of God. So then everyone who hears and learns from the Father comes to Me” (John 6:45).