What was the greatest spiritual gift when Paul wrote to the Corinthians?
At the time Paul wrote to the Corinthians, the greatest spiritual gift was prophecy—speaking forth the Word of God. Because the New Testament was not yet written, early apostolic churches depended on gifted men to proclaim Pauline doctrine and God's truth without the printed Scriptures.
Les explains that when Paul wrote to the Corinthians, the greatest spiritual gift was the gift to prophesy, or to speak forth the Word of God. At that time, no New Testament had been written; the Gospels would not be written until many years after Paul's letters, and Paul's own letters had not yet gone out as the Word of God. The early, primitive apostolic churches were growing and reaching out in the pagan world without the benefit of the written Word. They had to depend on gifted men, who had to be gifted enough to teach people the Pauline doctrines and not that which was still coming out of the Old Testament, or there would have been pandemonium. Paul, by inspiration, realized that the most important thing the local church could have was men who could proclaim the truth of God's Word without having it in print. So he said to desire the gift to proclaim the Word of God. But as he said in chapter 13, the time would come when that gift would fade away, and it is no longer a valid gift because now we have the printed page. We no longer need men gifted to proclaim the Word of God without anything to go on strictly by God's power, because now we have the Word of God.