Thou shalt not see a fierce people - Or, rather, ‘this fierce and boasting people you shall not see.’ They shall not enter the city; but though they are advancing with so much confidence, they shall be suddenly cut, off and destroyed. The word rendered “fierce,” (נועז nô‛âz from נעז yâ‛az), probably means strong, or wicked. Lowth renders it, ‘barbarous people,’ as if it were לועז lô‛ēz. Michaelis also adopts this reading by supposing an error in transcribing, a change of the Hebrew letter נ (n) into the Hebrew letter ל (l). Such a change might have easily occurred, but there is no authority from the manuscripts for making an alteration in the text The word strong, or mighty, agrees well with the connection.
A people of a deeper speech - A people whose language is so deep, that is, so dark, or obscure, that it cannot be understood by you. This refers to the army of the Assyrians, who spoke the Syrian language, which was understood by some of the Jews, but which was unintelligible to the mass (see Isaiah 36:11).
Than thou canst perceive - Than you can understand.
Of a stammering tongue - (see the note at Isaiah 28:11). Margin, ‘Ridiculous;’ a sense which the Hebrew will bear, but the more appropriate meaning is that of a barbarous, or unintelligible foreign language.