Isaiah 6:5

Isaiah is overwhelmed with the sense of his own unworthiness; he feels himself cut off by a spiritual defect from participation in the solemn mystery which he, alone of mortals, has been privileged to behold; his eyeshave seen, but his lipsare impure.

I am undone The Vulgate and other ancient versions give the impossible rendering, "I have been silent" (tacui). Jerome's paraphrase is interesting as explaining the genesis of a curious legend, that Isaiah had already been a prophet, but had lost the gift of inspiration through his unfaithfulness: "quia tacui et non audacter Osiam regem corripui, ideo labia mea immunda sunt."

a man of unclean lips "A pure lip" is required for the worship of Jehovah (Zephaniah 3:9); Isaiah would fain join in the praises of the Seraphim, but the impulse is checked by the uncleanness of his lips, which is the impurity of his whole nature concentrated, as it were, in the organs of expression. Isaiah is not yet a prophet; but in this profound sense of the necessity for a consecration of the faculty of speech we must surely recognise an unconscious preparation for the task of speaking the word of God.

a people of unclean lips Cf. ch. Isaiah 3:8. The vision of God which has brought his own sin to light, reveals to him also the sinfulness of the people among whom he dwells. They too are unfit to take the holy name of Jehovah on their lips; their whole worship of Him is profane. And this comes home to him as an aggravation of his guilt, that his mind is saturated with the atmosphere of ungodliness in which he lives and moves and has his being.

for mine eyes have seen the King A second ground for the ejaculation "I am undone!" That the sight of God brings death to men is an idea frequently expressed in the O.T. (Exodus 19:21; Exodus 30:20; Judges 13:22); the preceding clauses shew that to Isaiah's consciousness the danger springs from sin, and not from mere creaturely frailty.