Isaiah 29:1-24 is one of many chapters of Messianic prophecy whereby God would reveal Himself in the flesh as Jesus Christ (John 1:1-3, 14). We immediately know this is true by comparing what was prophesied by Isaiah in verse 13 and what Jesus said in the Gospel According to Matthew:
Wherefore the Lord said, Forasmuch as this people draw near me with their mouth, and with their lips do honour me, but have removed their heart far from me, and their fear toward me is taught by the precept of men. (Isaiah 29:13).
Ye hypocrites, well did Esaias prophesy of you, saying, This people draweth nigh unto me with their mouth, and honoureth me with their lips; but their heart is far from me. But in vain they do worship me, teaching for doctrines the commandments of men (Matthew 15:7-9).
Similarly, when we compare verse 14 to what the Apostle Paul wrote to the Corinthians, we see that Isaiah was talking about Jesus sacrificing Himself on the cross and salvation or, in other words, obeying the Gospel of Jesus Christ:
Therefore, behold, I will proceed to do a marvellous work among this people, even a marvellous work and a wonder: for the wisdom of their wise men shall perish, and the understanding of their prudent men shall be hid (Isaiah 29:14).
For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God. For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent (1 Corinthians 1:18-19)
People in Isaiah's time thought they could hide from God, that He didn't know "what's going on", "that He didn't see them" (Isaiah 29:15-16 NLT). Is that any different than today if we go to church for an hour on Sundays and then live like the devil the rest of the time, counting on His grace, without leading and living a repentant lifestyle, without dying daily (1 Corinthians 15:31)? The Apostle Paul says "God forbid" (Romans 6:1-23)!
In the next three verses (Isa. 29:17-19), the author returns to the prophesy of God revealing Himself as Jesus Christ to save humanity, Jews and Gentiles alike:
Then Isaiah prophesies that those who scorn Him and are offended by Him (Isa. 29:20-21) will be "cut-off" and "snared" (by the enemy). In other words, they will not be saved and will not make it to heaven. That will happen to anybody who does not obey the Gospel of Jesus Christ:
And to you who are troubled rest with us, when the Lord Jesus shall be revealed from heaven with his mighty angels, In flaming fire taking vengeance on them that know not God, and that obey not the gospel of our Lord Jesus Christ (1 Thessalonians 1:7-8).