"Moreover, brethren (believers in Corinth), I (the Apostle Paul) declare unto you the Gospel which I preached unto you, which also ye have received, and wherein ye stand: by which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain (believed when you heard, but then doubted - (Mt. 13:1-23). For I delivered unto you first of all that which I also received, how that Christ (the Messianic King longed for by the Jews - Mk. 14:61-62) died for our sins (Gal. 1:4; 1 Jn. 2:2) according to the scriptures (Ps. 22; Isa. 53; Dan. 9:26; Lk. 24:19-27); and that He was buried (Isa. 53:9; Mt. 27:57-61), and that He rose again the third day according to the scriptures (Ps. 16:10; Hos. 6:2): that He was seen of Cephas (Jn. 21:7), then of the twelve (Acts 1:2-3): after that, He was seen of above five hundred brethren at once (1 Cor. 15:6); of whom the greater part remain unto this present, but some are fallen asleep (have died)" (1 Cor. 15:1-5).
Note that it is the Gospel which, when believed, has the power of God to save the lost sinner (Rom. 1:16). When a believer presents the Gospel, the Holy Spirit convicts the hearer of his sin, of Christ's righteousness, and of the certain judgment that awaits those who reject Jesus (Jn. 16:7-11). We cannot win the lost by using enticing rhetoric (1 Cor. 2:4), because the agents of Satan are also capable of using enticing words to reject the truth (Col. 2:4). But we can, and must, present the simple Gospel message: because of God's love for us (Jn. 3:16), the self-sacrificing Lord deserves to be served and worshiped (Mt. 20:28; 1 Tim. 2:6; 1 Pet. 1:17; Rev. 4:11; 5:12)!
The Gospel is only "good news" to those whose lives are changed by it!