That Christ is God
In Genesis: “And God said unto Jacob, Arise, and go up to the place of Bethel, and dwell there; and make there an altar to that God who appeared unto you when thou reddest from the face of your brother Esau.” Also in Isaiah: “Thus says the Lord, the God of Sabaoth, Egypt is wearied; and the merchandise of the Ethiopians, and the tall men of the Sabeans, shall pass over unto You, and shall be Your servants; and shall walk after You bound with chains; and shall worship You, and shall pray to You, because God is in You, and there is no other God beside You.
For You are God, and we knew it not, O God of Israel, our Saviour. They shall all be confounded and fear who oppose You, and shall fall into confusion.” Likewise in the same: “The voice of one crying in the wilderness, Prepare the way of the Lord, make straight the paths of our God. Every channel shall be filled up, and every mountain and bill shall be made low, and all crooked places shall be made straight, and rough places plain; and the glory of the Lord shall be seen, and all flesh shall see the salvation of God, because the Lord has spoken it.” Moreover, in Jeremiah: This is our God, and no other shall be esteemed beside Him, who has found all the way of knowledge, and has given it to Jacob His son, and to Israel His beloved.
After this He was seen upon earth, and He conversed with men. Also in Zechariah God says: “And they shall cross over through the narrow sea, and they shall smite the waves in the sea, and they shall dry up all the depths of the rivers; and all the haughtiness of the Assyrians shall be confounded, and the sceptre of Egypt shall be taken away. And I will strengthen them in the Lord their God, and in His name shall they glory, says the Lord.” Moreover, in Hosea the Lord says: “I will not do according to the anger of mine indignation, I will not allow Ephraim to be destroyed: for I am God, and there is not a holy man in you: and I will not enter into the city; I will go after God.” Also in the forty-fourth Psalm: “Your throne, O God, is for ever and ever: the sceptre of righteousness is the sceptre of Your kingdom.
You have loved righteousness, and hated iniquity: wherefore God, Your God, has anointed You with the oil of gladness above Your fellows.” So, too, in the forty-fifth Psalm: “Be still, and know that I am God. I will be exalted among the nations, and I will be exalted in the earth.” Also in the eighty-first Psalm: “They have not known, neither have they understood: they will walk on in darkness.” Also in the sixty-seventh Psalm: “Sing unto God, sing praises unto His name: make a way for Him who goes up into the west: God is His name.” Also in the Gospel according to John: “In the beginning was the Word, and the Word was with God, and God was the Word.” Also in the same: “The Lord said to Thomas, Reach hither your finger, and behold my hands: and be not faithless, but believing.
Thomas answered and said unto Him, My Lord and my God. Jesus says unto him, Because you have seen me, you have believed: blessed are they who have not seen, and yet have believed.” Also Paul to the Romans: “I could wish that I myself were accursed from Christ for my brethren and my kindred according to the flesh: who are Israel-ires: whose are the adoption, and the glory, and the covenant, and the appointment of the law, and the service (of God), and the promises; whose are the fathers, of whom, according to the flesh, Christ came, who is God over all, blessed for evermore.” Also in the Apocalypse: “I am Alpha and Omega, the beginning and the end I will give to him that is thirsty, of the fountain of living water freely.
He that overcomes shall possess these things, and their inheritance; and I will be his God, and he shall be my son.” Also in the eighty-first Psalm: “God stood in the congregation of gods, and judging gods in the midst.” And again in the same place: “I have said, You are gods; and you are all the children of the Highest: but you shall die like men.” But if they who have been righteous, and have obeyed the divine precepts, may be called gods, how much more is Christ, the Son of God, God!
Thus He Himself says in the Gospel according to John: “Is it not written in the law, that I said, You are gods? If He called them gods to whom the word of God was given, and the Scripture cannot be relaxed, say to Him whom the Father has sanctified and sent into the world, that you blaspheme because I said, I am the Son of God? But if I do not the works of my Father, believe me not; but if I do, and you will not believe me, believe the works, and know that the Father is in me, and I in Him.” Also in the Gospel according to Matthew: “And you shall call His name Emmanuel, which is, being interpreted, God with us.”
Source: The Treatises of Cyprian (New Advent)