This is a great mystery. He concludes by expressing his astonishment at the spiritual union between Christ and the church. This is a great mystery; by which he means, that no language can explain fully what it implies. It is to no purpose that men fret themselves to comprehend, by the judgment of the flesh, the manner and character of this union; for here the infinite power of the Divine Spirit is exerted. Those who refuse to admit anything on this subject beyond what their own capacity can reach, act an exceedingly foolish part. We tell them that the flesh and blood of Christ are exhibited to us in the Lord's supper. "Explain to us the manner," they reply, "or you will not convince us." For my own part, I am overwhelmed by the depth of this mystery, and am not ashamed to join Paul in acknowledging at once my ignorance and my admiration. How much more satisfactory would this be than to follow my carnal judgment, in undervaluing what Paul declares to be a deep mystery! Reason itself teaches how we ought to act in such matters; for whatever is supernatural is clearly beyond our own comprehension. Let us therefore labor more to feel Christ living in us, than to discover the nature of that intercourse. We cannot avoid admiring the acuteness of the Papists, who conclude from the word mystery (musterion) that marriage is one of seven sacraments, as if they had the power of changing water into wine. They enumerate seven sacraments, while Christ has instituted no more than two; and, to prove that matrimony is one of the seven, they produce this passage. On what ground? Because the Vulgate has adopted the word Sacrament (sacramentum) as a translation of the word Mystery, which the apostle uses. As if Sacrament (sacramentum) did not frequently, among Latin writers, denote Mystery, or as if Mystery had not been the word employed by Paul in the same Epistle, when speaking of the calling of the Gentiles. But the present question is, Has marriage been appointed as a sacred symbol of the grace of God, to declare and represent to us something spiritual, such as Baptism or the Lord's Supper? They have no ground for such an assertion, unless it be that they have been deceived by the doubtful signification of a Latin word, or rather by their ignorance of the Greek language. If the simple fact had been observed, that the word used by Paul is Mystery, no mistake would ever have occurred. We see then the hammer and anvil with which they fabricated this sacrament. But they have given another proof of their indolence in not attending to the correction which is immediately added, But I speak concerning Christ and the church. He intended to give express warning that no man should understand him as speaking of marriage; so that his meaning is more fully expressed than if he had uttered the former sentiment without any exception. The great mystery is, that Christ breathes into the church his own life and power. But who would discover here anything like a sacrament? This blunder arose from the grossest ignorance.

This is a great mystery - The Latin Vulgate translates this, "sacramentum hoc magnum est" - "this is a great sacrament" - and this is the proof, I suppose, and the only proof adduced by the papists that marriage is a "sacrament." But the original here conveys no such idea. The word "mystery" - μυστήριον mustērion - means something which is concealed, hidden, before unknown; something into which one must be "initiated" or instructed before he can understand it. It does not mean that it is "incomprehensible" when it is disclosed, but that hitherto it has been kept secret. When disclosed it may be as intelligible as any other truth; see the word explained in the notes on Ephesians 1:9. Here it means simply, that there was much about the union of the Redeemer with his people, resembling the marriage connection, which was not obvious, except to those who were instructed; which was obscure to those who were not initiated; which they did not understand who had not been "taught." It does not mean that no one could understand it, but that it pertained to the class of truths into which it was necessary for one to be "initiated" in order to comprehend them. The truth that was so great a mystery was, that the eternal Son of God should form such an union with people; that he should take them into a connection with himself, implying an ardor of attachment, and a strength of affection superior to even that which exists in the marriage relation. This was a great and profound truth, to understand which, it was necessary to receive instruction. No one would have understood it without a revelation; no one understands it now except they who are taught of God.
But I speak concerning Christ and the church - This, it seems to me, is an explicit disclaimer of any intention to be understood as affirming that the marriage contract was designed to be a "type" of the union of the Redeemer and his people. The apostle says expressly, that his remarks do not refer to "marriage at all" when he speaks of the mystery. They refer "solely" to the union of the Redeemer and his people. How strange and unwarranted, therefore, are all the comments of expositors on this passage designed to explain marriage as "a mysterious type" of the union of Christ and the church! If people would allow the apostle to speak for himself, and not force on him sentiments which he expressly disclaims, the world would be saved from such insipid allegories as Macknight and others have derived from this passage. The Bible is a book of sense; and the time will come, it is hoped, when, freed from all such allegorizing expositions, it will commend itself to the good sense of mankind. Marriage is an important, a holy, a noble, a pure institution, altogether worthy of God; but it does not thence follow that marriage was designed to be a type of the union between Christ and the church, and it is certain that the apostle Paul meant; to teach no such thing.

This is a great mystery - Το μυστηριον τουτο μεγα εστιν· This mystery is great. Sacramentum hoc magnum est; this sacrament is great. - Vulgate. And on the evidence of this version the Church of Rome has made matrimony a sacrament, which, as they use it, is no meaning of the original. By mystery, here, we may understand a natural thing by which some spiritual matter is signified, which signification the Spirit of God alone can give. So, here, the creation and union of Adam and Eve, were intended, in the design of God, to point out the union of Christ and the Church: a union the most important that can be conceived; and therefore the apostle calls it a great mystery. See the observations at the end of this chapter, (Ephesians 5:33 (note)).

(15) This is a great mystery: but I speak concerning Christ and the church.
(15) That no man might dream of natural union or knitting of Christ and his Church together (such as the husbands and the wives is) he shows that it is secret, that is, spiritual and such as differs greatly from the common capacity of man. And it consists by the power of the Spirit, and not of the flesh, by faith, and by no natural bond.

This is a great mystery,.... It has something mysterious in it; it is a figure and emblem of the mysterious union between Christ and his people: for so it follows,
but I speak concerning Christ and the church; or mention this law and institution of marriage, with respect to them; for the leaving of father and mother prefigured Christ's coming forth from the Father, and coming into this world in human nature, and his disregard to his earthly parents, in comparison with his people, and his service for them; the man cleaving to the wife very aptly expresses the strong affection of Christ to his church, and the near communion there is between them; and their being one flesh denotes the union of them; and indeed, the marriage of Adam and Eve was a type of Christ and his church; for in this the first Adam was a figure of him that was to come, as well as in being a federal head to his posterity: Adam was before Eve, so Christ was before his church; God thought it not proper that man should be alone, so neither Christ, but that he should have some fellows and companions with him: the formation of Eve from Adam was typical of the church's production from Christ; she was made of him while he was asleep, which sleep was from the Lord, and it was not an ordinary one; which may resemble the sufferings and death of Christ, which were from the Lord, and were not common; and which are the redemption of his church and people; and which secure their comfort and happiness, and wellbeing: she was taken out of his side, and built up a woman of one of his ribs; both the justification and sanctification of the church are from Christ, from the water and the blood which issued out of his side, when on the cross: the bringing and presentation of Eve to Adam has its mystery; it was God that brought her to him; and she was the same that was made out of him; and to the same Adam was she brought of whose rib she was made, and that not against her will: so it is God that draws souls to Christ, and espouses them to him, even the same that he has chosen in him, and Christ has redeemed by his blood; and to the same are they brought, who was wounded for their transgressions, and bruised for their sins; and they are made willing in the day of his power upon them, to come and give themselves to him. Adam's consent and acknowledgment of Eve to be his wife, shadow forth Christ's hearty reception and acknowledgment of the saints, as being of him, and his, when they are brought unto him under the influences of his grace and Spirit.

Rather, "This mystery is a great one." This profound truth, beyond man's power of discovering, but now revealed, namely, of the spiritual union of Christ and the Church, represented by the marriage union, is a great one, of deep import. See on Ephesians 5:30. So "mystery" is used of a divine truth not to be discovered save by revelation of God (Romans 11:25; 1-Corinthians 15:51). The Vulgate wrongly translates, "This is a great sacrament," which is made the plea by the Romish Church (in spite of the blunder having been long ago exposed by their own commentators, CAJETAN and ESTIUS) for making marriage a sacrament; it is plain not marriage in general, but that of Christ and the Church, is what is pronounced to be a "great mystery," as the words following prove, "I [emphatic] say it in regard to Christ and to the Church" (so the Greek is best translated). "I, while I quote these words out of Scripture, use them in a higher sense" [CONYBEARE and HOWSON].