The modern versions all sadly go after another manuscript reading which says – ‘and to make all men see what is the dispensation of the mystery’. And that makes much less sense, and the King James Version and the older versions all go for the more authentic reading which says, ‘the fellowship of the mystery.
There is no change in God’s plan or in his intention over time. The gospel is not a change in direction for the purposes of God. It was there in the mind of Father, Son and Holy Spirit right from the start. We will find nothing in the Old Testament that is inconsistent with the gospel, but as Scripture unfolds it becomes more clear. In hindsight we see much which must have been mysterious to the saints of old, but for us who benefit from the further light that God has shed on his eternal purpose in Christ Jesus, we see that the Scripture always predicted the work of Christ as our Redeemer, and the gospel age when Jews and Gentiles would worship together as one flock. We live in the last age of earth’s history, the most privileged age in terms of revelation. God has now unveiled the full glory of his grace.