What is the Gospel? And How do we Obey the Gospel?

"Moreover, brethren, I 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. For I delivered unto you first of all that which I also received, how that 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:" - 1 Corinthians 15:1-4 [Emphasis added]

To be saved, we must OBEY the gospel.

"How then shall they call on him in whom they have not believed? and how shall they believe in him of whom they have not heard? and how shall they hear without a preacher? And how shall they preach, except they be sent? as it is written, How beautiful are the feet of them that preach the GOSPEL of peace, and bring glad tidings of good things! BUT THEY HAVE NOT ALL OBEYED THE GOSPEL. For Esaias saith, Lord, who hath believed our report?" - Romans 10:14-16

"So that we ourselves glory in you in the churches of God for your patience and faith in all your persecutions and tribulations that ye endure: ... And to you who are troubled rest with us, when the Lord Jesus shall be revealed from heaven with his mighty angels, in flaming fire taking vengeance on them that know not God, and that OBEY NOT THE GOSPEL of our Lord Jesus Christ:" - 2 Thessalonians 1:4, 7-8

"For the time is come that judgment must begin at the house of God: and if it first begin at us, what shall the end be of them that OBEY NOT THE GOSPEL of God?" - 1 Peter 4:17

Paul preached the gospel - Christ died for our sins, he was buried, and rose again.

How do we OBEY the gospel – Christ’s death, burial, and resurrection? Here is the answer:

"What shall we say then? Shall we continue in sin, that grace may abound? GOD FORBID. How shall we, that are DEAD TO SIN, live any longer therein? Know ye not, that so many of us as were BAPTIZED INTO JESUS CHRIST WERE BAPTIZED INTO HIS DEATH? THEREFORE we are BURIED WITH HIM BY BAPTISM INTO DEATH: that like as Christ was RAISED UP from the dead BY THE GLORY OF THE FATHER, even so we also should walk in NEWNESS OF LIFE. For if we have been planted together in the likeness of his death, we shall be also in the likeness of his RESURRECTION:

"Knowing this, that our old man [SINFUL NATURE] is CRUCIFIED with him, that the body of SIN might be DESTROYED, that henceforth we should NOT SERVE SIN. For he that is dead is FREED FROM SIN…

"Likewise reckon ye also yourselves to be DEAD indeed UNTO SIN, but ALIVE UNTO GOD through Jesus Christ our Lord." - Romans 6:1-7, 11 [Emphasis added]

Paul explains that Christ’s death, burial, and resurrection is obeyed by crucifying our old sinful nature by repentance and becoming dead to a sinful life; by burying our old sinful nature and sins with Jesus by water baptism in the name of Jesus for the remission of our sins; and by being raised to a new resurrected life by the glory of the Father, which is the infilling of the Holy Ghost (the Spirit of Jesus).

When asked, “What shall we do?”

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost." - Acts 2:38

"Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls. And they continued stedfastly in the apostles' doctrine and fellowship, and in breaking of bread, and in prayers. ... praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved." - Acts 2:41-42, 47