Was Jesus the biological son of Mary? If so, how did He not inherit a sin nature?

In the genealogy of Matthew Jesus Christ is shown to be the King legally; in the Gospel of Luke we have His genealogy as the Son of Man, and as such linked with the whole race. The genealogy in Matthew proves that Joseph is a descendant of David through the house of Solomon. The one in the Gospel of Luke proves that Mary, the virgin, is likewise a descendant of David, but not through the house of Solomon; she is connected with David through the house of Nathan. The Messiah was to be born of a virgin, one who must be a descendant of David. But a woman has no right to the throne. As the son of the virgin alone He could not have a legal right to the throne. For this reason to make the One begotten in her of the Holy Ghost, the rightful heir to the throne of David in the eyes of the nation, the virgin had to be the wife of a man who had a perfect, unchallenged right to the throne. Now the genealogy in Matthew shows that Joseph is a son of David, and thus entitled to the throne, therefore Jesus is legally in this way heir to the throne. He is the legal descendant and heir of David through Joseph, but never Joseph's Son. He was supposed by the people to be the Son of Joseph. "And Jesus Himself, when He began to teach, was about thirty years of age; being, as was supposed, the Son of Joseph" (Luke 3:23). "And they said, Is not this the Son of Joseph?" (Luke 4:22). His claim as being truly the Son of David was therefore never disputed. Now if He had been the Son of Joseph according to the flesh, He would never be and could never be our Saviour. The 51st Psalm would then have found an application. "I was shapen in iniquity and in sin did my mother conceive me." On the other hand, if He had been the Son of Mary, without she being legally the wife of a Son of David, the Jews would have rejected His claim from the very outset. We see then that legally He was the Son of Joseph; in His humanity, He is the Son of Mary, and then one step higher, as we read in the closing verses, He is the Son of God. The two genealogies show Him as King -- Son of man and Son of God -- as the One born of Mary, but begotten in her of the Holy Ghost.

The angel accordingly explains in all grace to Mary. "[The] Holy Spirit shall come upon thee,29 and power of [the] Highest overshadow thee." It was not to be nature, but Divine power. "Therefore the holy thing also which shall be born [of thee] shall be called Son of God," and not merely Son of man. This is exceedingly important. "Son of God" is a title that belongs to our Lord both in His Divine glory before He became a man and here; for, in this place when He became a man, He did not cease to be Son of God. As incarnate He was still the Son of God. So, again, when He rose from the dead, the same thing was true; He was the Son of God as risen again. It is plain therefore that it is a title that appertains to Him in the three conditions in which Scripture represents our Lord. He was the Son of God when He was purely and simply a Divine Person; Son of God when He became a man; Son of God when risen from the dead and gone out of this world to heaven. "Of thee," after "born" is supported only by C and a few minuscules.

But there is another thing also to note, that His taking manhood did not in the smallest degree connect Him with the taint of man's fallen nature. This was absolutely counteracted by the singularity of His conception, which was effected through the power of the Holy Ghost. "Wherefore the holy thing also which shall be born [of thee] shall be called Son of God."30 Thus He was holy, not merely in His Divine nature, but in His humanity. He was emphatically the Holy One of God: without this not only would salvation have been impossible for us, but even His own acceptance as man would have been out of the question."30a We have therefore in this passage the most important truth as to the birth of this wondrous Child, and the union of the Divine and human natures in the person of Christ. Much here given is peculiar to Luke. Mary is informed also of what God was doing to her cousin Elisabeth, for as the angel added "with God nothing shall be impossible."31 She bows at once to the will of the LORD, with the words, "Behold the bondmaid of [the] LORD; be it to me according to thy word. And the angel departed from her."

On the other hand Jesus had no sin. Although perfectly man, every thought, feeling, and inward motion was holy in Jesus: not only not a flaw in His ways was ever seen, but not a stain in His nature. Whatever men reason or dream, He was as pure humanly as divinely; and this may serve to show us the all-importance of holding fast what men call orthodoxy as to His person. I shall yield to none in jealousy for it, and loyally maintain that it is of the substance and essence of the faith of God's elect that we should confess the immaculate purity of His humanity just as much as the reality of His assumption of our nature. Assuredly He did take the proper manhood of His mother, but He never took manhood in the state of His mother, but as the body prepared for Him by the Holy Ghost, who expelled every taint of otherwise transmitted evil. In His mother that nature was under the taint of sin; she was fallen, as were all others naturally begotten and born in Adam's line. In Him it was not so; and in order that it should not be so, we learn in God's word that He was not begotten in a merely natural generation, which would have perpetuated the corruption of the nature and have linked Jesus with the fall; but by the power of the Holy Ghost He and He alone was born of woman without a human father. Consequently as the Son was necessarily pure, as pure as the Father, in His own proper divine nature, so also in the human nature which He thus received from His mother: both the divine and the human were found for ever afterwards joined in that one and the same person — the Word made flesh.

Wonder of wonders! Born of a sinful mother (for Mary herself humbly acknowledged her need of a Saviour — Luke 1:47), yet inheriting no moral taint from her. "A body hast Thou prepared Me; Lo, I come to do Thy will, O God" (Heb. 10:5-7). In Adam as originally created we see humanity innocent; in ourselves, fallen; in the Son of God; holy. Stainless in nature and in ways, death had no possible demand upon Him. But in His ineffable grace He submitted to the pangs of death that He might thereby make effectual atonement for human sin and guilt. Mere reason may well stagger in the presence of such a mystery as this; but herein is food for faith. "God was manifested in flesh" (1 Tim. 3:16). Shame on us that so infinite an expression of divine grace should be made a matter of mere idle cavil. Be it the part of every one of us to bow adoringly at His feet, like Thomas of old, exclaiming; "My Lord and my God" (John 20:28).

In the Gospels, where we naturally look for the complete, because inspired, historical accounts of the person of Christ, more particularly in the Gospel of Luke, where He is displayed specifically as man, we find the fullest evidence of this. "The angel answered, and said unto her [i.e., the Virgin Mary], the Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee; therefore also that holy thing which shall be born of thee shall be called [the] Son of God" (Luke 1:35). It is evident, therefore, though truly born of a woman, though deriving human nature from His mother Mary, there was, even in respect to this, a divine action which distinguished our blessed Lord most signally and strongly from all others from His birth. What Rome has lyingly, and as a thing of but yesterday, decreed of Mary, is most true of Jesus: He, not she, was immaculate in His human nature; and this through the energy of the Holy Ghost (as even the most rudimentary symbols of Christendom confess, I thank God), the result of the overshadowing power of the Highest. Hence therefore "That Holy Thing" could be its description from the first. He alone of all men was born "holy;" not made innocent and upright only, like Adam, still less — like Adam's sons — conceived in sin and shapen in iniquity. He is designated "That Holy Thing," it will be observed, when the question was not of what was simply divine (which indeed it would be wicked folly to doubt and needless to affirm here), but of what was human. "That holy thing which shall be born [of thee] * shall be called the Son of God."

His Birth (Luke 1:35).

"That holy thing that shall be born of thee shall be called the SON OF GOD." We have the birth of a Babe foretold here, conceived of the Holy Ghost, born of Mary the Virgin. He is here called Son of God as born in time. Though seen in the weakness of infancy, and so partaking in humanity perfectly, yet is He sinlessly holy; and He does not forfeit His Sonship by accepting human conditions. Had His mother been divine, He had not been human. She was woman, singularly favoured because chosen out of all the virgins of Israel to be the mother of the Lord; yet the more we make of Mary, the less do we make of the divine miracle of this holy birth. The body in which He appeared was prepared for Him (Heb. 10); and in it was He to effectuate all the will of God. It was guarded from every taint of sin in the Virgin's womb; not by any immaculate conception of the Virgin herself (as affirmed by Rome), which could be supposed to free her from taint of sin, but by the power and wisdom of God the Holy Ghost. The fable of the Virgin's immaculate birth, had it been true, would have required the same miracle in her parentage and birth which Scripture declares with regard to the Babe in David's royal city.

How this was secured, the Gospel of Luke bears witness for us. The power of the Holy Ghost accomplished what would otherwise have been impossible; and "that Holy Thing" born of the Virgin was, even as to His humanity, the "Son of God" (Luke 1:35). This does not of itself declare what John declares: it is not equivalent to the Word being made flesh. Luke's is the Gospel of the Manhood, as John's is of the Deity of the Lord. The one presents to us the First-born, as the other the Only-begotten. And it is essential to His proper glory that both sides should have adequate statement. The power of the Holy Ghost was manifested in the "Man Christ Jesus" being "made in all things like unto His brethren," while absolutely free from all the sad inheritance of the fall. It was manifested where needed: on the human side, and not on the divine.

This passage is profound, its subject sacred, and all comment upon it is attended with risk. But, surely, the action of the Holy Spirit was to exclude the poisonous taint otherwise derivable from Mary, and to ensure immaculate holiness for the One to be born by virtue of the miraculous conception. Moreover, the energy of the Deity was engaged in taking this holy humanity into indissoluble union with the Son. "Wherefore," said the angel, "the Holy Thing … shall be called Son of God."

Now I want you to fix your mind on that for a moment. It is the immutable law of God's creation that everything reproduces itself after its kind, and when Adam became a fallen sinner that law worked with deadly operation in all his descendants. We may be, as I said, the 150th generation from Adam, but we are just simply "after his kind", and we might go on reproducing ourselves, and thus project the first man and his race indefinitely into eternity, we should still only have fallen man. When the fifteen hundredth or the one hundred and fifty thousandth generation was reached it would still be "after his kind". You see — I think — what I am driving at. The awful entail of sin and death connected with the first man has ruined everything it touched with its blighting hand; and there never was a real and original second man until Jesus was born, and then the entail of sin and death was broken. He was conceived by the Holy Ghost's power. Discard the Virgin birth, and you have lost this great foundation truth of the Gospel.

For as sacrifice for sin He was sent, but therefore simply in the likeness, not in the reality, of flesh of sin, though as really a man born of woman as He was God. It was in that likeness, because He was born of a woman who, though a virgin of David's house, not less than any other human being, had flesh of sin. How then was the difficulty to be solved? By divine grace and power, through His conception by the Holy Spirit, our blessed Lord was to be as truly a man as any other, but not the sharer of human taint, nor, if I may so call it, of that attainder which had fallen on the race through sin. This was effected, as Luke 1 lets us know, by the power of the Highest overshadowing the virgin Mary; wherefore her Son was called the Son of God. This was absolutely essential. He must derive His flesh and blood really from His mother; but by that miraculous power, which wholly exempted His humanity from all spot or motion of evil, He in the truth of our nature was made like to us in all things, sin only excepted from which He was clearly void, both in His flesh and in His spirit. From that moment when the virgin was declared to be about to conceive and in due time become the mother of our Lord, a total immunity from sin was secured for Him: "A body didst Thou prepare for Me" (Heb. 10). Otherwise the sin-offering could not have been worthy of God, or efficacious for man. "It is most holy," was the voice even of the law respecting it: how much more was this true of Christ? Still He was in the likeness of flesh of sin, because His mother was certainly of sinful race like others, unless you prefer tradition or superstition to God's word.