Isaiah 6:5-7

Then said I, &c.— The second part of this vision contains the sanctification of the prophet for the undertaking of a great prophetical office, and consists of two parts: the first describes the prophet's state of mind upon the sight of the preceding illustrious vision: His consternation upon the sense of his great unworthiness. He expresses his fear of perishing, (I am undone,) because, being a man of unclean lips, and dwelling amongst an unclean people, he was therefore unfit to join in the celebration of the Godhead with the seraphim. The uncleanness of the lips means, not only offence in words, but the want of due qualifications for the important office in which he was to be employed. We have, secondly, in the 6th and 7th verses, the benefit of sanctification conferred upon the prophet by a singular mode of lustration. The idea is here again from the temple; and it has been generally allowed, that the live coal, or fire, is a symbol of the purifying and sanctifying grace of the Holy Spirit. See Acts 2:3.Matthew 3:11.; and this coal, taken from the altar, refers to the participation of the gift of the Spirit, as it proceeds from the merit of the great Sacrifice for the sins of the world. See Hebrews 9:14. The designation of Isaiah to the prophetical office is here particularly taught, and more remotely the sanctification of men to the ministry of the gospel; some of whom, like St. Paul, being men of impure lips, and unholy lives, are by the word of grace illuminated, sanctified, made holy and seraphic, and glowing with love and zeal for the glory of Christ. See Vitringa.