1 Corinthians 14:21

'In the law it is written, By men of strange tongues and by the lips of strangers will I speak to this people, and not even thus will they hear me, says the Lord.'

He now turns to the Scriptures quoting from Isaiah 28:11, either from some version that we do not have (it has similarities with Aquila's Greek translation), or as being paraphrased from the memory. This refers to the fact that in response to his opponents' suggestion that he, Isaiah, is speaking on the same level with little children and in childish language, God would deal with Israel in judgment by bringing against them armies of men who spoke strange tongues and who would speak with the lips of strangers with nothing to say to them. This referred to the Assyrian armies who would be God's instrument of judgment. They would hear these strange tongues at their gates, and rather than having anything to say to them the strange tongues would be a sign that they were doomed to judgment. This is how God would speak to them. They would hear strange tongues and recognise that they were about to suffer judgment because of their unbelief.