The word “gospel” simply means “good news.” The gospel is the historic, revealed message concerning Jesus Christ. It is that record of events which focuses upon Christ’s life, death, and resurrection for sinners. It is important to understand this as some Christians with good intentions maintain that believers should “live the gospel.”
Technically, one cannot live the good news of Christ’s life, death, and resurrection for sinners – it is a message, it is a declaration, it is good news. One can live in light of it or one can let his conduct be worthy of it or one can pursue holiness; but to live out the events of Christ’s redemptive work on behalf of sinners, is simply not our calling.
J. Gresham Machen said,
We can preach the gospel, they tell us, by our lives, and do not need to preach it by our words. But they are wrong. Men are not saved by the exhibition of our glorious Christian virtues; they are not saved by the contagion of our experiences. We cannot be the instruments of God in saving them if we preach to them thus only ourselves. Nay, we must preach to them the Lord Jesus Christ; for it is only through the gospel which sets Him forth that they can be saved.
In 1 Corinthians 15, the Apostle Paul addresses the doctrine of the resurrection. In verses 1-4, he sets forth the gospel of Jesus Christ as the foundation for the argument that follows. We note several things concerning the gospel in this section of Scripture.
In the first place, the gospel is rooted in history. Before the foundation of the world, God decreed to save a people by His Son Jesus Christ. The gospel is the execution of that decree in history. Paul says that Christ died, was buried, and rose again. These are historic, dateable, and non-repeatable events. In fulfillment of the Old Testament word of promise, Christ came in the fullness of the times, was born of a woman, and born under the law. He lived in obedience to the law of God, died to satisfy divine justice in the place of sinners, and rose again.
Secondly, the gospel is revealed by God. The Scripture speaks of two types of revelation, general and special. Psalm 19 and Romans 1 set forth the truth that God reveals Himself to His image bearers through the created order. The heavens declare the glory of God (Ps 19:1) and what God has manifested of Himself to man leaves man without excuse for his sin and disobedience (Rom 1:19-20). However, general revelation does not communicate the necessity for blood atonement. It does not reveal the work of Christ on the cross for sinners.
Special revelation is God’s having made Himself and His ways known through the Scriptures. Paul highlights this in 1 Corinthians 15:1-4 by indicating that Christ’s death, burial, and resurrection happened “according to the Scriptures” (vv.3,4). The work of Christ was not an after-thought or a reaction in the mind of God; the Old Testament conspicuously promised a coming Redeemer who would crush the head of Satan through His redemptive work which Christ carried out in His first coming.
Thirdly, the gospel is the record of Christ’s work for sinners. The Triune God is actively involved in salvation (Eph 1:3-14) and the gospel message is the outworking of the Father’s decree to save the elect. As well, it is the gospel that the Holy Spirit brings to bear upon the elect: when sinners are born again by His power, they believe the gospel of Christ. Because of this, the church and her preachers must set forth Christ in His person and in His work to all mankind. Paul determined to know nothing among the Corinthians “except Jesus Christ and Him crucified” (1 Cor 2:2); the modern church does well to imitate the Apostle.
Fourthly, the gospel is received by faith alone. Christianity is not moralism; it is not a message of “try-harder” and you will be accepted by God. The gospel addresses the root of the matter: man before God is completely undone because of his sin. There is no ability in the sinner to gain acceptance with God. The gospel is the revelation of the One who kept the law; who always did what pleased His Father; who died as a sacrifice and a substitute for His people.
The means by which His people are justified is through faith alone. Paul highlights the role of faith in 1 Corinthians 15 — “which also you received [by faith] in which you stand” (v.1), “by which also you are saved, if you hold fast that word which I preached to you—unless you believed in vain” (v.2) and “so we preach and so you believe” (v.11). Verse 2 also indicates the absolute necessity of the gospel for salvation, for if one does not believe and hold fast that word, one is not saved. Thankfully, the gift of faith (Eph 2:8-10; Phil 1:29) is also a benefit secured by Christ for the elect.
The final observation is a very practical one: the gospel is powerful to save the worst sinners. In verse 9, Paul writes, “For I am the least of the apostles, who am not worthy to be called an apostle, because I persecuted the church of God.” Paul declares in Romans 1:16 that the gospel “is the power of God to salvation for everyone who believes.” He highlights his own sinfulness in Galatians 1:13 and makes a wonderful declaration in 1 Timothy 1:15, “This is a faithful saying and worthy of all acceptance, that Christ Jesus came into the world to save sinners, of whom I am chief.” In light of these observations, we should praise God Almighty for His wonderful gospel!
 J. Gresham Machen, Education, Christianity, and the State (Jefferson: MD, The Trinity Foundation, 1987), p.21.
 Other passages speak to the absolute necessity of Christ and His gospel for salvation. See for example, Jn 14:6; Acts 4:12; Rom 1:16-17; Eph 1:13-14; Jas 1:18; 1 Pet 1:23.