And the mean man boweth down, and the great man humbleth himself: therefore forgive them not.
The mean man - in rank; not morally base: opposed "to the great man." The former is in Hebrew 'aadaam (H120); the latter, 'iysh (H376).
Boweth down - namely, to idols. All ranks were idolaters.
Therefore forgive them not - a threat expressed by an imperative. Isaiah so identifies himself with God's will that he prays for that which he knows God purposes. So Revelation 18:6.