The Inseparability of the Two Natures in Christ

The inseparability of the two natures, though not itself an essential mark of the Hypostatic Union, is an integral property of it.

A separation between the two natures is conceivable in only three ways: Christ’s manhood might have existed before its union with the Godhead and been united to it only later; the sacred manhood might have dissociated itself temporarily from the Logos at some point in the past; or the Logos might dissociate Himself from His manhood at some point in the future. All three are ruled out, as the following three theses show.

Thesis I: The Union Began at the Moment of Conception

This is an article of faith. A council held at Constantinople (A.D. 543) against the unorthodox teaching of Origen condemned as heretical the claim that Christ’s human nature existed prior to the Incarnation.¹ The Sixth Ecumenical Council defined: “In the Incarnation of the Word, the Godhead was not joined to flesh already animated beforehand, or already formed beforehand, or to a soul pre-existing beforehand … but [the flesh and soul] came into existence together with the Word Himself: at once flesh, at once flesh of God the Word; at once rational animated flesh, at once rational animated flesh of God the Word.”²

This has a solid Scriptural foundation: “made of the seed of David” (Romans 1:3) and “made of a woman” (Galatians 4:4) assert not only that Christ was true man, but that He became man precisely through His conception by the Virgin Mary — in the very instant of conception. Had the conception of the man Christ and the Incarnation of the Logos been separate, non-simultaneous events, Mary would not truly be Mother of God; she would have given birth to the Son of God, but not conceived Him — the Hypostatic Union would then have occurred sometime between conception and birth. St. Cyril saw this clearly, remarking against Nestorius: “The Blessed Virgin did not conceive a mere man, upon whom the Logos subsequently descended; rather, He subjected Himself to a carnal birth by a union that began in the maternal womb.”³ Pope St. Leo the Great states the dogma most sharply: “Our nature was not so assumed that it was first created and afterward assumed, but rather it was created by that very assumption.”⁴

Thesis II: The Logos Never Dissociated Himself from His Manhood, Even for an Instant

This is settled Catholic doctrine. The Sixth Ecumenical Council declared that Christ’s two wills and two operations are united inseparably; though the Council was directly defining the inseparable personal unity of Christ rather than the inseparability of the natures as such, the Eleventh Council of Toledo (675) removes any doubt: the two natures are “so united in themselves into the one Person of Christ, that neither can the Godhead ever be separated from the manhood, nor the manhood from the Godhead.” The Ethiopian liturgy states the same conviction simply: “I believe that the Godhead has never, even for an hour or a moment, been separated from the manhood.”

The Three Days in the Tomb

The only point at which the Hypostatic Union might conceivably have lapsed is the triduum mortis — the three days between Christ’s death and Resurrection. But the Apostles’ Creed itself settles the question: the dissolution of Christ’s human nature did not mean the cessation of the Hypostatic Union. “He was buried, and descended into hell” — His body was buried, His soul descended into hell. Christ’s death consisted in the separation of body from soul, not in the separation of His manhood from His Godhead; both body and soul, though temporarily parted from each other, each remained the true body and the true soul of the Son of God. Some heretics argued from Christ’s cry on the Cross — “My God, why hast thou forsaken me?” — that the Hypostatic Union was interrupted during the Passion, but this conclusion does not follow. Hugh of St. Victor, following the Fathers, explains: “God merely withdrew His protection; He did not sever the union.”⁵

The Precious Blood

A harder question: did the blood Christ shed during His Passion remain hypostatically united to the Logos during the triduum mortis?

It is theologically certain — though not a matter of strict faith — that in Christ’s living body, both before death and after the Resurrection, His sacred Blood was united to the Logos hypostatically and immediately, not merely mediately as with His hair or nails.⁶ Whether and how far blood is properly “informed” by the soul is a question physicians and philosophers have never fully settled — some hold blood merely an inanimate medium nourishing the tissues.⁷ Setting that dispute aside, it is theologically certain the Hypostatic Union extends to everything constituting the proper essence and integrity of human nature, not merely to whatever the soul directly informs; it would be a mistake to argue that only Christ’s nervous system was immediately united to the Logos while the rest of His body was united only mediately. Scripture tells us we were redeemed “with the Precious Blood of Christ,”⁸ the same Blood proposed for our adoration in the consecrated chalice at Mass. Pope Clement VI declares that, because of its union with the Divine Word, a single drop of Christ’s Precious Blood would have sufficed to redeem the world.⁹ St. Thomas states the common medieval view: “It is clear that the blood shed in the Passion, which was especially salutary, was united to the Godhead; and therefore it had to be rejoined, at the Resurrection, to the other parts of His humanity.”¹⁰

Whether the blood shed on the Cross specifically remained hypostatically united to the Logos during the triduum itself is harder to show. A sharp controversy on this point broke out between the Dominicans and Franciscans in the fifteenth century; Pope Pius II, in 1464, after a formal three-day debate, ordered both sides to stop quarreling and reserved the final decision to the Holy See¹¹ — a decision that was never issued. Since Trent, the Dominican view has prevailed: that during the triduum the Logos remained hypostatically united at least to the portion of His Precious Blood He reassumed at the Resurrection; the Franciscan counter-view no longer has prominent defenders outside Scotist circles.¹² Some older theologians held that Christ’s Blood was never at any time united to the Logos hypostatically at all — meaning that had the Apostles consecrated bread and wine during the triduum, it would have become mere blood, not the Blood of the God-man. This view is now considered obsolete. The Tridentine definition that Christ’s body and blood and soul all coexist under each Eucharistic species “by force of that natural connection and concomitance by which the parts of Christ the Lord … are united to one another”¹³ treats body and blood as standing on the same footing: either both are united to the Logos or neither is — and since Christ’s bloodless corpse remained truly the body of the Logos even in the tomb, the blood that had flowed from it cannot have been excluded from the Hypostatic Union either.

Various places — Jerusalem, Beirut, Rome, Mantua, Boulogne, Bruges, Weingarten, Reichenau, Stans, Neuvy-Saint-Sépulchre, and others — have claimed to possess relics of the Precious Blood.¹⁴ If genuine, such relics would only show that some particles of Christ’s blood were never reassumed and so permanently left the Godhead; they might be venerated as relics, as splinters of the True Cross are, but it would be idolatry to give them properly divine worship.¹⁵ St. Thomas himself leans toward doubting most such relics are genuine at all, suggesting the blood venerated in various churches “did not flow from Christ’s side, but is said to have flowed miraculously from some struck image of Christ.”¹⁶ Since the glorified Christ “dies no more” and sheds no more blood, such relics cannot be His actual Blood; Pohle adds a note of scientific caution here too — the phenomenon of “bleeding hosts” is sometimes explained by a rare microorganism, Serratia marcescens (then called Micrococcus prodigiosus), which produces blood-red spots on starchy foods like bread and hosts, giving rise to considerable medieval superstition.¹⁷

The axiom “what the Word once assumed, He never let go” applies without qualification only to Christ’s soul. Regarding His body, including the Precious Blood, it holds only relatively: the blood Christ shed at His circumcision, at the scourging, and in His agony at Gethsemane certainly left the union with His Godhead permanently — and this applies still more clearly to ordinary bodily secretions like tears, sweat, and the like.¹⁸

Thesis III: The Logos Will Never Dissociate Himself from His Manhood

This too is an article of faith. The Seleucians heretically taught that Christ had “transplanted His sacred humanity to the sun.”¹⁹ Marcellus of Ancyra and his disciple Photinus of Sirmium held that the Savior would divest Himself of His body once the resurrection of the flesh had occurred.²⁰ The Second General Council of Constantinople (A.D. 381) rejected this by adding to the Nicene Creed the phrase “of whose kingdom there shall be no end.”

Scripture

The perpetual inseparability of Christ’s two natures follows from Scripture’s teaching that Christ (the God-man, not merely the Logos in His eternity) is eternal, and that He is forever our High Priest and King. “Jesus Christ, yesterday, and today, and the same for ever” (Hebrews 13:8) — that this refers to the God-man rather than the Logos alone is clear from the accompanying teaching on Christ’s eternal priesthood: “But this one, because he continueth for ever, hath an everlasting priesthood” (Hebrews 7:24). He is likewise called eternal King: “And of his kingdom there shall be no end” (Luke 1:33). God Himself has sworn that the priesthood “according to the order of Melchisedech” will never end,²¹ and it is equally certain that Christ’s kingdom — the triumphant Church, His mystical body, together with her High Priest and King — will endure forever.

The Fathers

The unanimity of the Fathers on this point makes an extended argument from Tradition unnecessary. In his controversy with Marcellus of Ancyra, St. Cyril of Jerusalem denounces the new heresy as “another dragon’s head lately arisen in Galatia,” and concludes: “This hold fast, this believe; but what heresy has brought forth, that reject; for thou hast been most clearly instructed regarding the kingdom of Christ, which will never end.”²² St. John Chrysostom states it plainly: “[Christ] put on our flesh, not to put it off again, but to keep it forever.”²³

Further Reading

Assemani, Bibliotheca Orientalis, t. II, dissertation on the inseparability of Christ’s natures — Tepe, Institutiones Theologicae, Vol. III, pp. 541 sqq., Paris 1896 — Chr. Pesch, Praelectiones Dogmaticae, Vol. IV, 3rd ed., pp. 80 sqq., 95 sqq., Freiburg 1909 — L. Janssens, De Deo-Homine, Vol. I, pp. 294 sqq., Freiburg 1901.

Notes