Perceive not — The Hebrew words are imperative; yet they are not to be taken as a command what the people ought to do, but only as a prediction what they would do. The sense is, because you have so long heard my words, and seen my works, to no purpose, and have hardened your hearts, and will not learn nor reform, I will punish you in your own kind, your sin shall be your punishment. I will still continue my word and works to you, but will withdraw my Spirit, so that you shall be as unable, as now you are unwilling, to understand.
Related Commentaries of Isaiah 6:9
Isaiah 6:9
9 And he said, Go, and tell this people, Hear ye indeed, but understandd not; and see ye indeed, but perceive not.