I am not unaware, I went on to say, that you dare to expound even this Psalm as spoken of king Hezekiah, but that you are in error I will at once prove to you from the words themselves. We find: The Lord sware and will not repent, and Thou art priest for ever after the order of Melchizedek, and the context both before and after. But that Hezekiah has neither been, nor is, a priest of God for ever, not even you will dare to contradict. But that it is spoken about our Jesus, even the phrases themselves show. But your ears are stopped and your hearts are callous.Isaiah 6:10
For as for the phrase. The Lord sware, and will not repent; Thou art priest for ever after the order of Melchizedek, God, because of your unbelief, made it clear by an oath that He is High Priest after the order of Melchizedek, that is to say, that just as Melchizedek was written down by Moses as having been priest of God Most High, and was priest of those who were in uncircumcision, and blessed Abraham who was in circumcision and who offered him tithes, so did God make it clear that He who was called by the Holy Spirit His everlasting priest and Lord, should be (priest) of those who were in uncircumcision. And those who are in circumcision and go to Him, that is to say, believe Him and seek blessings from Him, them too will He accept and bless. And that He will first be a lowly man, and then be exalted, the words at the end of the Psalm make plain. For of a brook in the way shall He drink, and, at the same time, therefore shall He lift up His head.