Adam Clarke's Commentary on the Bible

Verse 9 (Isaiah 3:9)

The show of their countenance - Bishop Lowth has it the steadfastness of their countenance - they appear to be bent on iniquity, their eyes tell the wickedness of their hearts. The eye is the index of the mind. Envy, hatred, malice, malevolence, concupiscence, and murder, when in the heart, look most intelligently out at the eye. They tell the innocent to be on their guard; and serve the same purpose as the sonorous rings in the tail of the rattlesnake - they announce the presence of the destroyer.

They declare their sin as Sodom - Impure propensities are particularly legible in the eyes: whoever has beheld the face of a debauchee or a prostitute knows this; of these it may be said, they wish to appear what they really are. They glory in their iniquity. This is the highest pitch of ungodliness.

They have rewarded evil unto themselves - Every man's sin is against his own soul. Evil awaiteth sinners - and he that offends his God injures himself.

- Adam Clarke's Commentary on the Bible