Ephesians 3:4

Whereby, when ye read - When ye refer back to them.

Ye may understand my knowledge - Ye may see what God has given me to know concerning what has been hitherto a mystery - the calling of the Gentiles, and the breaking down the middle wall between them and the Jews, so as to make both one spiritual body, and on the same conditions.

Whereby, when ye read - By the bare reading of which you may understand the view which I entertain of the plan of salvation, and the knowledge which I have of God's method of saving people, particularly of his intention in regard to the salvation of the Gentiles.

In the mystery of Christ - This does not refer to anything "mysterious" in the person of Christ; or the union of the divine and human nature in him; or to anything difficult of apprehension in the work of the atonement. It means the hitherto concealed doctrine that through the Messiah, the Gentiles were to be received to the same privileges as the Jews, and that the plan of salvation was to be made equally free for all. This great truth had been hitherto concealed, or but partially understood, and Paul says that he was appointed to make it known to the world. His "knowledge" on the subject, he says, could be understood by what he had said, and from that they could judge whether he was qualified to state and defend the doctrines of the gospel. Paul evidently supposed that the knowledge which he had on that subject was of eminent value; that it was possessed by few; that it was important to understand it. Hence he dwells upon it. He speaks of the glory of that truth. He traces it back to the counsels of God. He shows that it entered into his eternal plans; and he evidently felt that the truth which he had communicated in the former part of this Epistle, was among the most important that could come before the mind.