who are wise in their own eyes
This phrase addresses the sin of pride and self-reliance. In the biblical context, wisdom is highly valued, but true wisdom comes from God (Proverbs 2:6). The people being addressed here are those who rely on their own understanding rather than seeking divine guidance. This self-reliance is condemned because it leads to moral and spiritual blindness. The phrase echoes Proverbs 3:7, "Do not be wise in your own eyes; fear the LORD and shun evil."

and clever in their own sight.
The term "clever" here is synonymous with being shrewd or cunning, often with a negative connotation. It suggests a reliance on human intellect and craftiness rather than on God's wisdom. This attitude is reminiscent of the serpent's cunning in Genesis 3, where human wisdom led to the fall. The phrase warns against the arrogance of thinking one can navigate life successfully without God's guidance. It also connects to the New Testament, where Paul warns against being "wise in your own sight" (Romans 12:16), emphasizing humility and dependence on God.

The opening “Woe” announces God’s solemn warning and impending judgment. In Isaiah 5 the Lord pronounces six such woes (vv. 8, 11, 18, 20, 21, 22), each exposing a particular sin corrupting Judah. This same prophetic tone appears in Isaiah 10:1 and later on Jesus’ lips in Matthew 23:13-36. A “woe” is not a casual scolding; it signals that God’s patience has reached its limit and that consequences are certain unless repentance follows. Like Habakkuk 2:12 or Revelation 8:13, the word carries grief for the sinner and righteous anger against the sin.

Self-declared wisdom replaces humble dependence on God:

• Proverbs 3:7 says, “Do not be wise in your own eyes; fear the LORD and turn away from evil.”

• Proverbs 26:12 points out that a fool has more hope than the person who thinks he already has all the answers.

• Romans 1:22 pictures unbelieving humanity: “Although they claimed to be wise, they became fools.”

When people trust their own judgment above Scripture they:

– redefine right and wrong (see Judges 17:6),

– dismiss God’s counsel as outdated (1 Corinthians 1:20-25),

– and stir up division because they will not heed correction (Romans 12:16). The Lord’s indictment here is literal: anyone who leans on human reasoning while ignoring divine revelation invites the very “woe” proclaimed.

“Clever” suggests a showy, self-congratulatory shrewdness. It is the attitude that says, “I can outsmart consequences.” Yet Isaiah 29:15 warns, “Woe to those who go deep to hide their plans from the LORD.” Worldly ingenuity cannot hide rebellion from God:

• Proverbs 14:12 reminds us, “There is a way that seems right to a man, but its end is the way of death.”

• 1 Corinthians 3:19 adds, “The wisdom of this world is foolishness in God’s sight.”

• James 3:15-17 contrasts earthly, self-seeking wisdom with the pure, peace-loving wisdom that comes from above.

Isaiah’s phrase highlights the danger of intellectual pride: people convince themselves they are too sophisticated to submit to God’s clear commands, yet that very confidence blinds them to truth (John 9:39-41).

Isaiah 5:21 confronts the sin of arrogant self-reliance. God pronounces a serious “woe” on all who elevate their own opinions above His revealed Word, celebrating cleverness while disregarding the Creator. True wisdom begins with humble reverence for the Lord (Proverbs 9:10) and is perfectly expressed in Christ, “in whom are hidden all the treasures of wisdom and knowledge” (Colossians 2:3). Listening to Him spares us the woe reserved for those who remain wise only in their own eyes.