47 The Only-begotten God, then, suffered in His person the attacks of all the infirmities to which we are subject; but He suffered them in the power of His own nature, just as He was born in the power of His own nature, for at His birth He did not lose His omnipotent nature by being born. Though born under human conditions, He was not so conceived: His birth was surrounded by human circumstances, but His origin went beyond them. He suffered then in His body after the manner of our infirm body, yet bore the sufferings of our body in the power of His own body. To this article of our faith the prophet bears witness when he says, He bears our sins and grieves for us: and we esteemed Him stricken, smitten, and afflicted: He was wounded for our transgressions and made weak for our sins. It is then a mistaken opinion of human judgment, which thinks He felt pain because He suffered. He bore our sins, that is, He assumed our body of sin, but was Himself sinless. He was sent in the likeness of the flesh of sin, bearing sin indeed in His flesh but our sin. So too He felt pain for us, but not with our senses; He was found in fashion as a man, with a body which could feel pain, but His nature could not feel pain; for, though His fashion was that of a man, His origin was not human, but He was born by conception of the Holy Ghost.
For the reasons mentioned, He was esteemed 'stricken, smitten and afflicted.' He took the form of a servant: and 'man born of a Virgin' conveys to us the idea of One Whose nature felt pain when He suffered. But though He was wounded it was 'for our transgressions.' The wound was not the wound of His own transgressions: the suffering not a suffering for Himself. He was not born man for His own sake, nor did He transgress in His own action. The Apostle explains the principle of the Divine Plan when he says, We beseech you through Christ to be reconciled to God. Him, Who knew no sin, He made to be sin on our behalf. To condemn sin through sin in the flesh, He Who knew no sin was Himself made sin; that is, by means of the flesh to condemn sin in the flesh, He became flesh on our behalf but knew not flesh: and therefore was wounded because of our transgressions.
Source: On the Trinity (New Advent)