John Calvin on Isaiah 28:11

11. For with stammering lips. {Bogus footnote} Some supply, that “it is as if one should say;” but that is superfluous. I therefore view these words as relating to God, who became, as the Prophet tells us, a barbarian {Bogus footnote} to a people without understanding. This reproof must have wounded them to the quick, because by their own fault they made God, who formed our tongues, to appear to be “a stammerer.” He does not as yet threaten them, but lays the blame on their indolence, that they rendered the proclamation of heavenly doctrine a confused noise, because of their own accord they shut their eyes, and thus derived no advantage from it. Their infatuation, in not hearing God speaking to them, is compared by the Prophet to a prodigy.