Translated by P.E. Pusey
2. How we must understand Emmanuel.
God the Word is named Emmanuel, because He laid hold of the seed of Abraham and like as partook of flesh and blood. Now Emmanuel is interpreted, With us is God. But we confess that the Word of God was with us, not locally (for in what place is God not, Who fills all things?) nor because He is seen to come to us by way of aid (for thus was it said to Jesus, As I was with Moses, so I will be, with thee too), but because He was made in our condition, i. e. in human nature, without forsaking His own Nature, for the Word of God is Unchangeable in Nature.
But why was it, when it was said to Jesus, As I was with Moses, so I will be with thee, that he was nevertheless not called Emmanuel? this is the reason, even though He be said to be with any of the saints. We therefore say that He God the Word became with us, at that time of which Baruch says, He did shew Himself upon earth and conversed with men, and found out all the way of instruction and gave it to Jacob His servant and to Israel His beloved, for He is our God and there shall none other be accounted of in comparison with Him. As far then as pertained to His being God by Nature, He was not with us; for incomparable is the difference between Godhead and manhood and exceeding great the difference of the natures.
And therefore was the Divine David calling to Mystic relationship God the Word Who had not as yet come to us and saying in spirit, Why hast Thou departed far from us, O Lord, despisest us in season in tribulation? Therefore He departed not  from us, but was with us, Who while He remained what He was, took hold of the seed of Abraham, as I said; received moreover the form of a servant, and was beheld as Man upon the earth.
But Christ and Emmanuel signify to us the Same Son, the one, because He was anointed as we in human wise, receiving the Spirit for the nature of man in Himself first (for He is set forth as the first beginning of the race), Himself again anointing, as God, with the Holy Ghost those who believe in Him; the other, because He was with us in the way I have explained, whereof the Prophet Isaiah tells us saying, Behold a Virgin shall conceive and bear a Son and shall call His Name Immanuel. For when the holy Virgin conceived out of the Holy Ghost, but bare according to the flesh a Son, then too was He called Emmanuel; for the Incorporeal was with us by carnal birth, and that took place which was told by David, God shall appear openly, our God and shall not be silent, and that (I deem), I Who speak am at hand. For the Word spake through the Prophets as yet Unembodied, He came Embodied.
4. [d] In his first Paschal homily, some fifteen years before (A. D. 414) S. Cyril had quoted this verse and explained it, "For the Saviour having not vet assumed our likeness, was departed far from us, as regards the plan of the Incarnation: since much is the interval between the nature of man and that of God the Word: for of us says one of the saints, I am earth and ashes, of the Being of the Only-Begotten the prophet Isaiah says, who shall declare His Generation? Seasonably therefore on us in our much affliction beamed the Saviour made of a woman after the flesh, in order to save man who is out of woman, and that, loosing him from the bonds of death, He might teach him to say rejoicing, where thy victory death, where thy sting o grave?" Hom. Pasch. i. pp. 4e 5 a.
Reference address : https://www.elpenor.org/cyril-alexandria/incarnation-only-begotten.asp?pg=2