Here is a short selection of verses about the gospel. It is always an interesting exercise to compare your 'gospel' with the bible's, to see what is missing, what is underplayed, what is over-emphasised perhaps in your own attempts to present the gospel. This list is by no means comprehensive (and of course, simply listing the verses that mention 'gospel' is not the best way to give a full definition of what the gospel is anyway), but still should provide some food for thought and a little taste of the dazzling, multi-faceted unity of God's gospel.
Mar 1:1 The beginning of the gospel of Jesus Christ, the Son of God.
Mar 1:14-15 Now after John was arrested, Jesus came into Galilee, proclaiming the gospel of God, and saying, "The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel."
Act 20:24 But I do not account my life of any value nor as precious to myself, if only I may finish my course and the ministry that I received from the Lord Jesus, to testify to the gospel of the grace of God.
Rom 1:1-4 Paul, a servant of Christ Jesus, called to be an apostle, set apart for the gospel of God, which he promised beforehand through his prophets in the holy Scriptures, concerning his Son, who was descended from David according to the flesh and was declared to be the Son of God in power according to the Spirit of holiness by his resurrection from the dead, Jesus Christ our Lord,
Rom 1:16-17 For I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek. For in it the righteousness of God is revealed from faith for faith, as it is written, "The righteous shall live by faith."
Rom 2:16 on that day when, according to my gospel, God judges the secrets of men by Christ Jesus.
1Co 15:1-8 Now I would remind you, brothers, of the gospel I preached to you, which you received, in which you stand, and by which you are being saved, if you hold fast to the word I preached to you--unless you believed in vain. For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures, and that he appeared to Cephas, then to the twelve. Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. Then he appeared to James, then to all the apostles. Last of all, as to one untimely born, he appeared also to me.
2Co 4:4 In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God.
Gal 1:6-9 I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel--not that there is another one, but there are some who trouble you and want to distort the gospel of Christ. But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed. As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed.
Gal 3:8 And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, "In you shall all the nations be blessed."
Eph 1:13 In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit,
Eph 3:6-7 This mystery is that the Gentiles are fellow heirs, members of the same body, and partakers of the promise in Christ Jesus through the gospel. Of this gospel I was made a minister according to the gift of God's grace, which was given me by the working of his power.
Eph 6:15 and, as shoes for your feet, having put on the readiness given by the gospel of peace.
Phi 4:15 And you Philippians yourselves know that in the beginning of the gospel, when I left Macedonia, no church entered into partnership with me in giving and receiving, except you only.
Col 1:5 because of the hope laid up for you in heaven. Of this you have heard before in the word of the truth, the gospel,
1Ti 1:11 in accordance with the glorious gospel of the blessed God with which I have been entrusted.
2Ti 1:10 and which now has been manifested through the appearing of our Savior Christ Jesus, who abolished death and brought life and immortality to light through the gospel,
2Ti 2:8 Remember Jesus Christ, risen from the dead, the offspring of David, as preached in my gospel,
Rev 14:6-7 Then I saw another angel flying directly overhead, with an eternal gospel to proclaim to those who dwell on earth, to every nation and tribe and language and people. And he said with a loud voice, "Fear God and give him glory, because the hour of his judgment has come, and worship him who made heaven and earth, the sea and the springs of water."