Having made known to us the mystery of his will. Some were alarmed at the novelty of his doctrine. With a view to such persons, he very properly denominates it a mystery of the divine will, and yet a mystery which God has now been pleased to reveal. As he formerly ascribed their election, so he now ascribes their calling, to the good pleasure of God. The Ephesians are thus led to consider that Christ has been made known, and the gospel preached to them, not because they deserved any such thing, but because it pleased God. Which he hath purposed in himself. All is wisely and properly arranged. What can be more just than that his purposes, with which men are unacquainted, should be known to God alone, so long as he is pleased to conceal them, -- or, again, that it should be in his own will and power to fix the time when they shall be communicated to men? The decree to adopt the Gentiles is declared to have been till now hidden in the mind of God, but so hidden, that God reserved it in his own power until the time of the revelation. Does any one now complain of it as a new and unprecedented occurrence, that those who were formerly "without God in the world," (Ephesians 2:12,) should be received into the church? Will he have the hardihood to deny that the knowledge of God is greater than that of men?

Having made known to us the mystery of his will - The word "mystery" (μυστήριον mustērion) means literally something into which one must be "initiated" before it is fully known (from μυέω mueō, to initiate, to instruct); and then anything which is concealed or hidden. We commonly use the word to denote that which is above our comprehension or unintelligible. But this is never the meaning of the word in the New Testament. It means there some doctrine or fact which has been concealed, or which has not before been fully revealed, or which has been set forth only by figures and symbols. When the doctrine is made known, it may be as clear and plain as any other. Such was the doctrine that God meant to call the Gentiles, which was long concealed, at least in part, and which was not fully made known until the Saviour came, and which had been until that time "a mystery - a concealed truth" - though when it was revealed, there was nothing incomprehensible in it. Thus, in Colossians 1:26, "The mystery which hath been hid from ages and from generations, but now is made manifest to his saints." So it was in regard to the doctrine of election. It was a mystery until it was made known by the actual conversion of those whom God had chosen. So in regard to the incarnation of the Redeemer; the atonement; the whole plan of salvation. Over all these great points there was a veil thrown, and people did not understand them until God revealed them. When they were revealed, the mystery was removed, and men were able to see clearly the manifestation of the will of God.
Which he hath purposed in himself - Without foreign aid or counsel. His purposes originated in his own mind, and were concealed until he chose to make them known; see 2-Timothy 1:9.

Having made known unto us the mystery - That the Gentiles should ever be received into the Church of God, and have all the privileges of the Jews, without being obliged to submit to circumcision, and perform the rites and ceremonies of the Jewish law was a mystery - a hidden thing which had never been published before; and now revealed only to the apostles. It was God's will that it should be so, but that will he kept hidden to the present time. A mystery signifies something hidden, but it ceases to be a mystery as soon as it is revealed. See the note on Matthew 13:11; and particularly that on Romans 11:25 (note).
Good pleasure - Την ευδοκιαν· That benevolent design which he had purposed in himself, not being induced by any consideration from without.

Having made known unto us the (m) mystery of his will, (13) according to his good pleasure which he hath purposed in himself:
(m) For unless the Lord had opened to us that mystery, we could never have so much as dreamed of it ourselves.
(13) Not only the election, but also the calling proceeds from grace alone.

Having made known unto us the mystery of his will,.... The Gospel, which is a mystery, a hidden mystery, the mystery of God and of Christ, and the mystery of the Gospel; the several doctrines of it are called the mysteries of the kingdom of heaven; such as are concerning the trinity of persons in the Godhead, the union of the two natures in Christ, his sonship and incarnation, the saints' union and communion with him, the work of the Spirit of God upon the soul, the calling of the Gentiles, and the conversion of the Jews, the resurrection of the dead, and the change of living saints: and the Gospel is the mystery of the will of God; of his will in saving sinners by Christ; and it declares that he does all things in salvation, according to his sovereign will and pleasure; chooses, redeems, justifies, pardons, and calls whom he pleases; and this is made known by the ministry of the word, and by the Spirit, as a spirit of wisdom and revelation, in the knowledge of Christ and his Gospel: the discovery of which is,
according to his good pleasure, which he hath purposed in himself; both with respect to the persons to whom it is made known, and with respect to the time when he makes it known; both these are as he pleases, and as he has purposed in his own breast; the Gospel is sent when and where he has determined within himself it shall go; and persons are called by it according to his purpose and grace.

Blessings were made known to believers, by the Lord's showing to them the mystery of his sovereign will, and the method of redemption and salvation. But these must have been for ever hidden from us, if God had not made them known by his written word, preached gospel, and Spirit of truth. Christ united the two differing parties, God and man, in his own person, and satisfied for that wrong which caused the separation. He wrought, by his Spirit, those graces of faith and love, whereby we are made one with God, and among ourselves. He dispenses all his blessings, according to his good pleasure. His Divine teaching led whom he pleased to see the glory of those truths, which others were left to blaspheme. What a gracious promise that is, which secures the gift of the Holy Ghost to those who ask him! The sanctifying and comforting influences of the Holy Spirit seal believers as the children of God, and heirs of heaven. These are the first-fruits of holy happiness. For this we were made, and for this we were redeemed; this is the great design of God in all that he has done for us; let all be ascribed unto the praise of his glory.

"He hath abounded," or "made (grace) to abound toward us" (Ephesians 1:8), in that He made known to us, namely, experimentally, in our hearts.
the mystery--God's purpose of redemption hidden heretofore in His counsels, but now revealed (Ephesians 6:19; Romans 16:25; Colossians 1:26-27). This "mystery" is not like the heathen mysteries, which were imparted only to the initiated few. All Christians are the initiated. Only unbelievers are the uninitiated.
according to his good pleasure--showing the cause why "He hath made known to us the mystery," namely, His own loving "good pleasure" toward us; also the time and manner of His doing so, are according to His good pleasure.
purposed-- (Ephesians 1:11).
in himself--God the Father. BENGEL takes it, "in Him," that is, Christ, as in Ephesians 1:3-4. But the proper name, "in Christ," Ephesians 1:10, immediately after, is inconsistent with His being here meant by the pronoun.

Having made known to us - By his word and by his Spirit. The mystery of his will - The gracious scheme of salvation by faith, which depends on his own sovereign will alone. This was but darkly discovered under the law; is now totally hid from unbelievers; and has heights and depths which surpass all the knowledge even of true believers.