Epiphanius Ancoratus 3

The word scares those people who are not deemed worthy of the Holy Spirit for its says: and no one can say, “Jesus is Lord,” except by the Holy Spirit (1Cor. 12.3). Even the Jews says the name of Jesus but they do not think He is Lord. You will find that the Arians do not have the Holy Spirit when they say He is God by name but He is adopted and not the true God. So if one does not receive the Holy Spirit, they cannot say Jesus is really Lord, and truly God, and truly the Son of God, and the eternal King. Well, let them who have perverse opinions understand this: the Only-Begotten Son desires not to testify concerning Himself. He spoke of such in the Gospel: If I alone testify about Myself, My testimony is not true. There is another who testifies of Me (Jn. 5.31).  Who is this other He speaks of? Namely, the One who spoke from heaven! This is My beloved Son, in whom I am well-pleased (Matt. 3.17; cf. Matt. 17.5). He also says: Even if I testify about Myself, My testimony is true (Jn. 8.14); and again, the very works that I do—testify about Me, that the Father has sent Me (Jn. 5.36); and again, For if you believed Moses, you would believe Me, for he wrote about Me (Jn. 5.46); and He is saying it is Moses that testifies about Him.  Let’s start with the first statement: If I alone testify about Myself, My testimony is not true. Therefore, this is said in order to exclude the tendency for some men to be arrogant and vain and recommend themselves vying to win the trust of each other through boasting.  When he says: Even if I testify about Myself, My testimony is true, He is showing us that what He says has no origin in men but is the testimony of God.  We can only conclude the Father is really and truly God, the Son is really and truly God and the Holy Spirit is really and truly God, the Spirit of God “who is,” and also the Spirit of Truth, the Trinity in unity, including the Spirit. The Son speaks of His Father in this way: that they may know You, the only true God (Jn. 17.3). The trustworthy witness who leans on His Father’s breast and calls Him His  Only-Begotten God. He did not add to the Only-Begotten God “true God,” but in regard to the Father the Son is Only-Begotten God. Again He says about the Father that God is Light and regard to the Son, that He is the True Light.