Vigilius of Thapsus — on Wis 16:21 (Against Marivadus the Arian, PL 62)

“Where they say that the Son was not born from the substance of the Father. But if they should say: the Son was not born from the paternal substance, but generated from another substance. Response. We also, who confess the Father and the Son to be of one substance, have taught by divine authority that the Son is from the substance of God the Father, as the prophet Jeremiah says: "Take up mourning over the minds, and lamentation over the paths of the desert, because they have failed, since they are not men; because they were unwilling to hear the voice of my substance, from the birds of the sky even to the beasts they have fallen away in mind" (Jer. 9:10). Likewise there: "Who has stood in the substance of the Lord, and will see the word of God? Who has given ear and heard" (Jer. 23:18)? And there: "If they had stood in my substance, and if they had heard my words, and if they had taught my people, I would have turned them away from their most evil pursuits" (Jer. 23:22). And the Apostle: "Who, being the radiance of glory and the form of his substance" (Heb. 1:3). Likewise he himself: "For we have become partakers of God; let us hold fast the beginning of his substance" (Heb. 3:14). And in Solomon: "My substance is my sweetness" (Wis. 16:21). From this, then, recognize that he who is called the substance of God the Father is not believed to be foreign to that same substance.”