John Trapp on Isaiah 28:9

Ver. 9. Whom ſhall he teach knowledge?] Quem docebit ſcientiam? Doceo governeth two Accuſative caſes. Miniſters muſt have 1. Quem, whom to teach: and 2. Quid, what to teach, ſc. Knowledge. Iſaiah had no want of knowledge, as being apt and able to teach, but he wanted a fit Audience, as having to do with a ſort of drunken ſots that were unteachable, uncapable. So Ezek. 47.11. when the waters of the Sanctuary flowed, the miry places could not be healed. Think the ſame alſo of thoſe that are drunk with pride (as ver. 1.) and ſelf-conceitedneſs, who make Divinity only a matter of diſcourſe, or that come to ſit as Judges or Criticks on their Miniſters gifts, &c. It will be long enough ere ſuch will be taught any thing. One may as good undertake to teach a young weanling void of underſtanding; and in ſome reſpects better; for theſe to their natural corruption and impotency have added habitual hardneſs and obſtinacy, to their ſinews of iron, brows of braſs, Iſaiah 48.4. and what hope can there be of working upon ſuch?