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.

Note the Gospel message comprises six elements:

1. Jesus Christ, the Son of God died; implies we need to acknowledge that it was the Son of God who died, not just anyone.

2. Jesus died for our sins, because we are all sinners: it is the Holy Spirit that convicts a person of his or her sins, and the need for salvation.

3. That Jesus died for our sins is recorded in the Scripture, both in the Old Testament and the New.

4. Jesus was certainly dead, in that he was buried and indeed his grave was sealed and watched over by solders.

5. Jesus rose again three days after his burial; just as was prophesied in the Old Testament, and by Jesus himself. The certainty of his resurrection is what gives a believer hope that they someday also will be raised from the dead (1 Cor. 16:14). This fact is central to the gospel message (1 Cor. 15:16-19)

6. Jesus was seen alive by many, in particular Cephas (Simon Peter) and the twelve disciples, so we have ample witnesses that these events took place, which included around 500 other people, some of whom have died.

The jailer asked: "Sirs, what must I do to be saved?" And they (Paul and Silas) said, "Believe in the Lord Jesus, and you will be saved (Acts 16:30,31)