In the year that king Uzziah died, I saw, &c.— We have in this chapter the fourth sermon, containing an account of a wonderful and august vision wherewith the prophet was favoured by the Lord: The design of which is two-fold; to exhibit a figure of the kingdom of the Son of God, hereafter to be manifested in the world, and to foretel the future blindness and hardness of heart of the greatest part of the Jewish nation. There are three parts of this discourse. The first contains a symbolical manifestation of the glorious Majesty of the God of Israel, Isaiah 6:1-4.; the second, the sanctification of Isaiah to the performance of an important prophetic office, Isaiah 6:5-7.; the third, a peculiar command which the prophet received from God, concerning the future and unhappy state of the Jews, 8-13. There seems to be no doubt that this vision is to be immediately referred to the times of the gospel, though it is possible that it has some reference also to the men of Isaiah's own time. See Vitringa.
I saw also the Lord sitting upon a throne, high and lifted up— In this first part of the vision, we have the species of revelation which happened to the prophet, which he calls a vision, but in which the prophet seems to have been rather passive than active;—and the object of the vision, which consists of various parts: first, the appearance of Jehovah, sitting on a lofty throne, clothed as it were with a royal robe, the skirts of which filled the temple: Secondly, of the seraphim next to the throne, celebrating the majesty and greatness of God; Isaiah 6:2-3. And, thirdly, the consequences of this glorious appearance; the commotion of the posts of the temple, and its repletion with smoke, Isaiah 6:4. The place of this vision is supposed to be in the temple. We are not to imagine that Isaiah saw the Godhead itself, but some symbolical representation of it, most likely the appearance of Christ in the human form in glory. See John 12:41. For there seems to be no doubt, from the description, that the appearance was human. See Vitringa, and Waterland's sixth sermon on the Trinity.