I was reading in Thomas Manton today and discovered some very interesting thoughts on the above topic. Here are the relevant passages:
In the hypostatical union, our nature is united with Christ’s nature; in the mystical union, our person with his person. In the hypostatical union, Christ matched into our family; in the mystical union, the soul is the bride…Thus Christ first honoured our nature, and then our persons; first he assumeth our nature, and then espouseth our persons…The hypostatical union is indissoluble; it was never laid aside, not in death; it was the Lord of glory that was crucified, it was the body of Christ in the grave. So it is in the mystical union; Christ and we shall never be parted…In the hypostatical union, the human nature can do nothing apart from the divine; no more can we out of Christ…In the hypostatical union, God dwelleth in Christ σωματικῶς, Col. 2:9 “In him dwelleth all the fulness of the Godhead bodily.” In the mystical union, God dwelleth in us πνευματικῶς, 1 John 4:4 “Greater is he that is in you, than he that is in the world.” The hypostatical union is the ground of all that grace and glory that was bestowed on the human nature…By the hypostatical union, Christ is made our brother, he contracted affinity with the human nature; by the mystical union he is made our head and husband, he weddeth our persons. Volume XI of his complete works, pp. 35-36.
Incidentally, I came across another quotation on baptism in Manton that cuts against the grain of the Federal Vision:
We are ‘baptized into Christ,’ Galatians 3:27. It is the pledge of our admission into that body whereof Christ is the head. God is aforehand with us; we were engaged to make a profession of this union, before we had liberty to choose our own way. Let us not retract our vows, and make baptism only a memorial of our hypocrisy, to profess union when there is no such matter. Emphasis added, p. 68 of the same volume.