“You say right: as therefore He made Him, Who knew not sin, sin for us, in order that WE might be made the righteousness of God in Him (for the nature of man has been justified in Him): so Him Who knows not death (for the Word is Life and life-giving) He caused to suffer in the flesh, though He remained external to suffering in that He is conceived of as God, in order that we might live through Him and in Him. Hence also the suffering of Christ has been named, ‘the likeness of death.’ It is written therefore, For if we have been co-planted in the likeness of His death so shall we be too of His resurrection: for the Word was living, even while His holy flesh was tasting death in order that, death worsted and decay trodden down, the might of the resurrection might come unto the whole human race. For it is true, that as in Adam all die so too in Christ all shall be brought to life. Since, how do we say that the Mystery of the Economy with flesh of the Only-Begotten aided man’s nature, unless the Word being God has been made flesh? Unless He Who is above all the creation lowered Himself unto emptying and hath come down to be in our estate? Unless that have been made the body of Life which is subject to decay in order that it might become superior to death and decay?” St. Cyril of Alexandria, On The Unity of Christ
We notice here that the essential aspect of the Incarnation is the Logos coming into our humanity, and uniting with it. He becomes all that we are that we might become what He is. Life enters into death that it might destroy death. Unless the Living God had come into the body and suffered its afflictions, it would not have been healed of them by His unity with it (His humanity). This is developed in this article He Took Our Infirmities and Bore Our Diseases – A Theology of Healing.