1 Corinthians 15:3
For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
Note 7 at 1Co 15:3: The New International Version renders the first part of this verse as "For what I received I passed on to you as of first importance." So, Paul was not just speaking of the first things he told these Corinthians, but he was rehearsing the most important things he had shared with them. Among these most important things was the death, burial, and resurrection of Jesus. Certainly, the virgin birth of Jesus, salvation by grace through faith, and many other great truths of salvation could have been included, but Paul was reminding them of these facts to establish the truth of the resurrection.
Note 8 at 1Co 15:3: It is one of the great truths of the Bible that Jesus died for man's sins, not for His own. Jesus was totally sinless (2Co 5:21, Heb 4:15, and 1Pe 2:22). This is one of the major differences between Christianity and the religions of the world. No other religious leaders have ever claimed to be sinless; therefore, no other religious leaders are even in the same class with Jesus.
Also, no other religious leaders have ever given their lives in sacrifice to atone for the sins of others. It wouldn't have done any good if they had. Since the religious leaders were and are sinners themselves, their lives aren't worth any more than any other sinner. However, since Jesus was the sinless Son of God, His life was worth more than all of humanity of all ages.
The sinless Son of God giving His pure life for mankind is truly one of the unique aspects of the Gospel.
Note 9 at 1Co 15:3: Every detail of Christ's death, burial, and resurrection was already prophesied in Scripture before it happened. Paul didn't just report historical facts to the Corinthians; he shared how all the events of Jesus' life, death, and resurrection had fulfilled Scripture. God's Word is the ultimate authority, and only through His Word can people receive faith (Ro 10:17) to be born again (1Pe 1:23). Believers must preach the Word, not experiences. Experiences are only useful to illustrate that God's Word is true.