35 We have now seen the power that lay in the acts and words of Christ. We have incontestably proved that His body did not share the infirmity of a natural body, because its power could expel the infirmities of the body that when He suffered, suffering laid hold of His body, but did not inflict upon it the nature of pain: and this because, though the form of our body was in the Lord, yet He by virtue of His origin was not in the body of our weakness and imperfection. He was conceived of the Holy Ghost and born of the Virgin, who performed the office of her sex, but did not receive the seed of His conception from man. She brought forth a body, but one conceived of the Holy Ghost; a body possessing inherent reality, but with no infirmity in its nature. That body was truly and indeed body, because it was born of the Virgin: but it was above the weakness of our body, because it had its beginning in a spiritual conception.
Source: On the Trinity (New Advent)