This oracle of Yahweh, via Isaiah, centers on insincere worship. They adore the Lord with their mouths and lips, but their hearts are far away. They only praise the Lord because of human demands, as they recite rote prayers. However, Yahweh, the Lord, was going to do marvelous, amazing, and shocking things for his people. The wisdom of the wise would perish, while the discernment of the discerning was hidden.
Psalm 101 is a psalm of David. David sings of loyalty and justice to Yahweh. He wants to be blameless, but he knows that he has not attained it yet. Perhaps this was a psalm for a king to recite before his coronation.
This is one of the few times where God speaks directly to the wicked. It is usually about them. He asked them what right they had to recite his statutes. What right did they have to put the covenant on their lips? The wicked hated discipline. They put God’s word behind them. They made friends with thieves and adulterers. This is a strong direct description and rebuke of the wicked.