"Christianity, you see, isn't a set of ideas. It isn't a path of spirituality. It isn't a rule of life. It isn't a political agenda. It includes, and indeed gives energy, to all those things; but at its very heart it is something different.
"It is Good News about an event which has happened in the world, an event because of which the world can never be the same again. And those who believe it, and live by it, will -- thank God! -- never be the same again either." (N.T. Wright, Paul for Everyone: 1 Corinthians, p. 206)
Let me now remind you, dear brothers and sisters,* of the Good News I preached to you before. You welcomed it then, and you still stand firm in it. 2 It is this Good News that saves you if you continue to believe the message I told you—unless, of course, you believed something that was never true in the first place.*
3 I passed on to you what was most important and what had also been passed on to me. Christ died for our sins, just as the Scriptures said. 4 He was buried, and he was raised from the dead on the third day, just as the Scriptures said. 5 He was seen by Peter* and then by the Twelve. 6 After that, he was seen by more than 500 of his followers* at one time, most of whom are still alive, though some have died. 7 Then he was seen by James and later by all the apostles. 8 Last of all, as though I had been born at the wrong time, I also saw him. 9 For I am the least of all the apostles. In fact, I’m not even worthy to be called an apostle after the way I persecuted God’s church.
10 But whatever I am now, it is all because God poured out his special favor on me—and not without results. For I have worked harder than any of the other apostles; yet it was not I but God who was working through me by his grace. 11 So it makes no difference whether I preach or they preach, for we all preach the same message you have already believed.
-- The Apostle Paul to the believers at Corinth (Holy Bible: New Living Translation; 1 Corinthians 15:1–11)