According to Michael King, at the beginning of his ministry, Isaiah was taken to the temple to meet the Lord and receive his commission to teach the people. Much of the imagery used by Isaiah reflects an intimate understanding of the ceremony and symbolisms of the tabernacle as well as of latter-day temples. Isaiah uses this understanding to teach the ordinances of the temple that are necessary so that God may fulfill his covenant with members of the house of Israel and provide them a way to return to him.
Isaiah "saw the Lord sitting upon a throne" surrounded by seraphim, or cherubim. As "the posts of the door moved," Isaiah became self-conscious and felt unworthy to enter into the Lord's presence. Isaiah no doubt had an understanding of the tabernacle and knew that only the high priest, on the Day of Atonement, was allowed to enter the Holy of Holies, or presence of the Lord. As the high priest approached the entrance of the Holy of Holies, he encountered the veil, on which were embroidered cherubim, which symbolized sentinels to guard the way into the presence of God. In order to enter, the priest would strike the posts with blood from an animal that had been slain as atonement for the sins of the people. Perhaps this was what Isaiah witnessed as he described the posits of the door moving. He realized that he was being invited to enter into the presence of the Lord. It is no wonder that he would exclaim, "Woe is me! for I am undone. . . for mine eyes have seen the King, the Lord of Hosts" (Isaiah 6:5). [Michael L. King, "Isaiah's Vision of God's Plan to Fulfill His Covenant," in Covenants Prophecies and Hymns of the Old Testament, pp. 169]