John Calvin Commentary Isaiah 57:4

"Against whom do ye sport yourselves? against whom make ye a wide mouth, and put out the tongue? are ye not children of transgression, a seed of falsehood," — Isaiah 57:4 (ASV)

On whom have you made sport? The Prophet shows that there is no reason why the Jews should boast so proudly on the pretense of their birth, since they mocked God and the prophets. They thought that they had to deal with men when they rejected the word; as we see that wicked men today, while they fearlessly despise the doctrine of God and laugh at ministers, nevertheless shelter themselves and falsely glory in the name of God. This is the reason why the Prophet deals harshly with them and censures them severely.

On whom have you opened the mouth? The meaning of the words is, “When you put out the tongue against God and mock his word, do you think that you have to deal with a mortal man?” The question (“On whom?”) means that they resorted to disguises and concealments to conceal their impiety; for wicked men do not confess that they are rebels against God, and even complain that they are very unjustly treated. But they must be dragged to the light and convicted of their wickedness; for if there is a God in heaven, they carry on war with him by attacking and rejecting his word and treating it as a fable.

To “open the mouth” and to “put out the tongue” mean the same thing, except that with these expressions he has more fully described their wickedness, in not only rejecting God but also mocking him. The inward contempt of the heart had driven them to open jeers and blasphemies, so that they were not moved by any fear of disgrace.

Seed of the adulterer and the whore. Finally, he concludes that they are treacherous children, a lying seed, and that he has justly reproached them with being “the children of the whore;” for such contempt of God could not be found in the children of Abraham. Hence we learn how wicked men ought to be treated, and with what severity they ought to be reproved, so that they do not flatter themselves; and the more they despise everything that is offered in the name of God, the more their sacrilegious wickedness ought to be exposed and dragged out to public view.