Since when was the mystery hidden in God?
The mystery was hidden in God from the beginning of the world, that is, from Adam. Scripture states it was veiled and covered up in God, not made known in other ages or generations, until it was revealed by the Spirit to the apostles and prophets.
Les explains that the mystery, or secret, was hid in God from the beginning of the world, that is, from Adam. It was not made known to the sons of men in other ages or generations; it was kept under wraps and veiled. Then by revelation, the Lord made it known to the apostle, unveiling the fellowship of the mystery—that the Gentiles should come in under God's grace. This shows there was a time when no one knew these things.