The root of the Greek word which is translated "gospel," is euaggelion, and it means "good news." It is the same root that is translated "evangelist." It appears one hundred one times as "gospel," and three times as "evangelist." It is obvious then that the work of an evangelist was, and is, to present the good news to the lost world. The Apostle Paul presents the most concise explanation of the message which is described as good news. In 1 Corinthians 15:1-4, Paul reminds the Corinthians that the gospel he preached produced salvation to all who believed. He then repeats what he had already taught them. "...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" The good news then is that Jesus died, was buried, and rose again to life in three days, just as He had predicted (Matthew 12:40), and faith in Him brings salvation.
Salvation from what? Salvation from death caused by the enmity (separation) between God and man. From the day Adam sinned, a sin nature was passed on to all men, for all have sinned (Romans 3:23). Separation from God by sin was revealed to Israel in the Law of Moses. Paul describes the Law as a schoolmaster to bring us to Christ (Galatians 3:24). The Law convinced us that we were hopelessly lost, because no mere human is able to live a perfect life. We need a Savior. The good news is that we have One. Jesus died according to the Scriptures (the Old Testament). Jesus was buried and rose again the third day according to the Scriptures.
Israel's idea of a savior was an earthly king who would defeat Israel's enemies and establish His world government. What they failed to understand was that they had a much greater enemy: themselves. They had spent fifteen hundred years covering their sins with the blood of animals, but their sins needed more than a covering; Israel (and all humans) needed to have them totally removed. The good news is that Jesus came to do just that. By trusting in His death, burial, and resurrection as payment for sins, they gained eternal life. Israel was right to expect the Messiah to come take control of the world, but like most of us, they neglected to include all of the Scripture. They apparently ignored those describing the Messiah's death (Psalm 22; Isaiah 53; and Daniel 9). He chose to die for us during His first appearance so that we could spend more than a mere lifetime in an earthly kingdom (which will begin at His second appearing). He rose from the dead to guarantee all who believe in Him will spend eternity with Him. Good News: God loves you enough to sacrifice His only begotten Son so that all that believe will live with Him forever (John 3:16). Praise the Lord!