John Gill Commentary Isaiah 5:21

"Woe unto them that are wise in their own eyes, and prudent in their own sight!" — Isaiah 5:21 (ASV)

Woe unto [them that are] wise in their own eyes And yet betray such stupidity and sottishness, as to call things by their wrong names; and make such a perverse judgment of them, as before described. This is a true description of the Scribes and Pharisees in Christ's time; who said, "do you teach us? are we blind also?" (John 9:34–40) and prudent in their own sight; being wise above what was written; leaving the word of God, and following the traditions of the elders.