In the law it is written, With men of other tongues and other lips will I speak unto this people; and yet for all that will they not hear me, saith the Lord. In the law it is written - But the passage quoted is in Isaiah 28:11. Here is no contradiction, for the term תירה torah, Law, was frequently used by the Jews to express the whole Scriptures, law, prophets, and hagiographia; and they used it to distinguish these sacred writings from the words of the scribes.
With men of other tongues - Bishop Pearce paraphrases this verse as follows: "With the tongues of foreigners and with the lips of foreigners will I speak to this people; and yet, for all that, will they not hear me, saith the Lord." To enter into the apostle's meaning we must enter into that of the prophet. The Jewish people were under the teaching of the prophets who were sent from God; these instructed, reproved, and corrected them by this Divine authority. They however became so refractory and disobedient that God purposed to cast them off, and abandon them to the Babylonians: then, they had a people to teach, correct, and reprove them, whose language they did not understand. The discipline that they received in this way was widely different from that which they received while under the teaching of the prophets and the government of God; and yet for all this they did not humble themselves before their Maker that this affliction might be removed from them.