After the Lord Jesus Christ accomplished His judicial redemption and initiated His organic salvation through His death on the cross and His resurrection, He charged His disciples (including we who have believed into Him) to preach the gospel. (Matthew 28:19, Mark 16:15) This is a solemn charge to every believer.
The early Christians took this charge seriously, as Acts 5:42 says that “…they did not cease teaching and announcing the gospel of Jesus as the Christ.” The Apostle Paul did also: “To me, less than the least of all saints, was this grace given to announce to the nations the unsearchable riches of Christ as the gospel” (Ephesians 3:8).
The gospel that we preach is that by the vicarious death of Jesus Christ on the cross He has cleansed all those who come to Him through faith from every sin, and has fulfilled all the requirements of God’s righteousness. Through His resurrection Jesus Christ became the life-giving Spirit to impart the eternal, divine life of God into everyone who believes into Him, thus making us God’s sons, both in life and nature.