Why does it matter that the Old Testament prophets didn't understand the Gospel of Grace?
It matters because God kept the Gospel of Grace secret from the Old Testament prophets. They searched diligently but did not understand, ministering instead to us. If they had understood, the verse in Romans 16 would be almost spurious. Their ignorance confirms Scripture's truth and God's hidden purpose.
Les teaches that the Old Testament prophets inquired and searched diligently concerning the salvation and grace that should come to us. The Spirit of Christ in them testified beforehand of Christ's sufferings and the glory that would follow, but it was revealed that they ministered these things not to themselves but to us. God never intended them to understand the Gospel of Grace; He had been keeping it secret. Les directs us to Romans 16, where the theme verse shows that if the prophets had understood—and if Abraham had seen Christ die, rise, and offer salvation to the whole world—that verse would be almost spurious. But it is not; it is the truth. Their lack of understanding matters because it validates the secret, hidden nature of the Gospel of Grace and the reliability of Scripture.
Searching what, or what manner of time the Spirit of Christ which was in them did signify, when it testified beforehand the sufferings of Christ, and the glory that should follow.
Unto whom it was revealed, that not unto themselves, but unto us they did minister the things, which are now reported unto you by them that have preached the gospel unto you with the Holy Ghost sent down from heaven; which things the angels desire to look into.
More Questions
Why could the Old Testament prophets not understand their own prophecies?
The Old Testament prophets could not put it all together—they did not fully understand how the Messiah's suffering and the coming glory fit together.