Speaking of the unbelief of the Jews, the Evangelist immediately explains the causes of their unbelief in this way: "Therefore they could not believe in Him, because Isaiah said, You shall hear with hearing, and shall not understand; and seeing you shall see, and shall not perceive." He said this when he saw the glory of the Only-begotten and bore witness concerning Him (Is 6:9-10; Jn 12:40-41). Therefore, in the present passage, the One who commands Isaiah to say, "You shall hear with hearing, and shall not understand," is He who sits upon the throne. The One who gives this command, as the Evangelist understands, is Christ. From this it is now clear that the Seraph cannot be understood as Christ, since Christ Himself is the One seated. In the Acts of the Apostles, speaking against the Jews who were disputing among themselves, Paul says: "Well did the Holy Spirit speak through Isaiah the Prophet to our fathers, saying, Go to this people and say: You shall hear with hearing and shall not understand; and seeing you shall see and shall not perceive. For the heart of this people has grown dull, and with their ears they scarcely hear, and their eyes they have closed; lest they should see with their eyes and hear with their ears, and understand with the heart, and turn to Me, and I should heal them" (Acts 28:25 and following). Yet the distinction of person does not perplex me, since I know that both Christ and the Holy Spirit are of one essence. The words of the Spirit are none other than those of the Son, and the Son commanded no differently than the Spirit.