This mystery of the incarnation of the Son of God was thus completed, I say, that he might be in all points like as we are, yet without sin; for sin in the flesh disableth and maketh incapable to do the commandment. Therefore was he thus made, thus made of a woman; and this the angel assigneth as the reason of this his marvellous incarnation. 'The Holy Ghost,' saith he, 'shall come upon thee, and the power of the Highest shall overshadow thee; therefore also that holy thing that shall be born of thee shall be called the Son of God' (Luke 1:35).
The overshadowing of the Holy Ghost and the power of the Highest—the Father and the Holy Ghost—brought this wonderful thing to pass, for Jesus is a wonderful one in his conception and birth. This mystery is that next to the mystery of three persons in one God; it is a great mystery. 'Great is the mystery of godliness: God was manifest in the flesh.'
The conclusion is, that Jesus Christ took our flesh that he might be our Saviour; and that he might be our Saviour indeed, he thus took our flesh.
That it was necessary that he should take our flesh if he will be our Saviour.
Third. I come now to the third thing—namely, that it was necessary that he should take our flesh if he will be our Saviour.
1. And that, first, from the nature of the work; his work was to save, to save man, sinking man, man that was 'going down to the pit' (Job 33:24). Now, he that will save him that is sinking must take hold on him. And since he was not to save a man, but men, therefore it was necessary that he should take hold, not of one person, but of the common nature, clothing himself with part of the same. He took not hold of angels, 'but he took on him the seed of Abraham' (Heb 2:16). For that flesh was the same with the whole lump of the children to whom the promise was made, and comprehended in it the body of them that shall be saved, even as in Adam was comprehended the whole world at first (Rom 5).
Hence we are said to be chosen in him, to be gathered, being in him, to be dead by him, to be risen with him, and to be set with him, or in him, in heavenly places already (Rom 7:4; Eph 1:4,10; Col 2:12,13, 3:1-3). This, then, was the wisdom of the great God, that the Eternal Son of his love should take hold of, and so secure the sinking souls of perishing sinners by assuming their flesh.
2. The manner of his doing the work of a Saviour did call for his taking of our flesh.
He must do the work by dying. 'Ought not Christ to have suffered? Christ must needs have suffered,' or else no glory follows (Luke 24:26; Acts 17:3). 'The prophets testified beforehand the sufferings of Christ, and the glory that should follow' (1 Peter 1:11). Yea, they did it by the Spirit, even by the Spirit of Christ himself. This Spirit, then, did bid them tell the world, yea, testify, that Christ must suffer, or no man be blest with glory; for the threatening of death and the curse of the law lay in the way between heaven gates and the souls of the children, for their sins; wherefore he that will save them must answer Divine justice, or God must lie, in saving them without inflicting the punishment threatened. Christ, then, must needs have suffered; the manner of the work laid a necessity upon him to take our flesh upon him; he must die, he must die for us, he must die for our sins. And this was effectually foretold by all the bloody sacrifices that were offered under the law—the blood of bulls, the blood of lambs, the blood of rams, the blood of calves, and the blood of goats and birds. These bloody sacrifices, what did they signify, what were they figures of, but of the bloody sacrifice of the body of Jesus Christ? their blood being a shadow of his blood, and their flesh being a shadow of his flesh.
Therefore, when God declared that he took no pleasure in them, because they could not make the worshippers perfect as pertaining to the conscience, then comes Jesus Christ to offer his sinless body and soul for the sin of the people—'For it is not possible that the blood of bulls and of goats should take away sin. Wherefore, when he cometh into the world, he saith, Sacrifices and offering thou wouldest not, but a body hast thou prepared me; in burnt-offerings and sacrifices for sin thou hast had no pleasure. Then said I, Lo, I come, in the volume of the book it is written of me, to do thy will, O God.' Since burnt-offerings cannot do thy will, my body shall; since the blood of bulls and goats cannot do thy will, my blood shall. Then follows, By the will of God 'we are sanctified, through the offering up of the body of Jesus Christ once for all' (Heb 10:4-10).