Why the Third Day in 1 Corinthians 15:3–4
Paul does not give the third day as a calendar curiosity but as part of the scripturally shaped message he received and passed on. The raising on the third day belongs to the good news itself, announced beforehand in the Scriptures.
If Christ Has Not Been Raised: 1 Corinthians 15
Paul will not let the Corinthians keep a risen Christ while denying the resurrection of the dead. In 1 Corinthians 15:12–20 he shows that the two stand or fall together, then answers every loss with the turn of verse 20: Christ has been raised, the first fruits of those who are asleep.
What Is the Gospel? 1 Corinthians 15:1–4
The gospel is not a method or a feeling but the announced message Paul preached: Christ died for our sins, was buried, and was raised on the third day, all according to the Scriptures. The Corinthians received this word and stand in it, and it is the word by which they are saved if they hold it firmly.