The roads are deserted. He now adds, that "the roads" will be shut up, so that no one shall go in or out; which commonly happens when war has been declared. The Prophet appears to represent the ambassadors as declaring that henceforth there will be no opportunity of carrying on merchandise, and even that the highways will not be safe. [1] It is immediately added, -- They have violated the treaty. These words are viewed by some commentators as a complaint made by hypocrites that God does not fulfill his promises. If it were thought proper to view them as referring to God, still it would not be necessary to say that such a complaint proceeds from none but wicked men; for sometimes believers also quarrel with God in this manner. But I cannot approve of that interpretation; and, therefore, consider this to be a part of the description which the Prophet gives of the cruelty and insatiable rage of Sennacherib, in treacherously breaking the treaty which he had formerly made with Hezekiah; for, although he had promised that he would maintain peace, yet as soon as an opportunity presented itself for invading Judea, he violated his promise and made preparations for war. Such is also the import of the conclusion of the verse, that he hath despised the cities, he hath regarded no man, which means that his cruelty will be so great that he will not be restrained by shame or fear.

Footnotes

1 - "These are not the words of the ambassadors reporting the condition of the country (Grotius), but of the Prophet himself describing it. The scene presented is not that of Protestant cities seized by Antichrist, and a stop put to a religious course and conversation (Gill), but the actual condition of Judea during the Assyrian invasion. (Compare Judges 5:6)." -- Alexander.

The highways lie waste - This verse contains a description of the desolations that had been caused by the invasion of Sennacherib. Some have understood it as containing the account which the ambassadors sent by Hezekiah gave of the effects of the invasion. Thus Grotius interprets it. But it is probably a description made by the prophet himself, and is designed to state one cause why the messengers that had been sent out wept bitterly. They had not only failed of inducing Sennacherib to abandon his purpose of attacking Jerusalem, but they had witnessed the effects of his invasion already. The public ways were desolate. In the consternation and alarm that was produced by his approach, the roads that had been usually thronged were now solitary and still. A mournful desolation already prevailed, and they apprehended still greater calamities, and hence, they wept.
The wayfaring man ceaseth - Hebrew, 'He that passes along the road ceases.' That is, there is a cessation of travel. No one is seen passing along the streets that used to be thronged.
He hath broken the covenant - This may either mean that the Assyrian king had violated the compact which had been made with him by Ahaz, by which he was to come and aid Jerusalem against the allied armies of Syria and Samaria (see the notes at Isaiah. 7), or it may mean that he had violated an implied compact with Hezekiah. When Judea was threatened with an invasion by Sennacherib, Hezekiah had sent to him when he was at Lachish, and had sought for peace 2-Kings 18:14. In that embassy Hezekiah said, 'I have offended, return from me; that which thou puttest on me I will bear. And the king of Assyria appointed unto Hezekiah king of Judah three hundred talents of silver and thirty talents of gold.' To pay this, Hezekiah exhausted his treasury, and even stripped the temple of its golden ornaments 2-Kings 18:15-16. A compact was thus made by which it was understood that Sennacherib was to withdraw his army, and depart from the land. But notwithstanding this, he still persisted in his purpose, and immediately despatched a part of his army to lay siege to Jerusalem. All the treaties, therefore, had been violated. He had disregarded that which was made with Ahaz, and that which he had now himself made with Hezekiah, and was advancing in violation of all to lay siege to the city.
He hath despised the cities - That is, he disregards their defenses, and their strength; he invades and takes all that comes in his way. He speaks of them with contempt and scorn as being unable to stand before him, or to resist his march. See his vain and confident boasting in Isaiah 10:9; Isaiah 36:19.
He regardeth no man - He spares no one, and he observes no compact with any man.

The (n) highways lie waste, the wayfaring man ceaseth: he hath broken the covenant, he hath despised the cities, he regardeth no man.
(n) These are the words of the ambassadors, when they returned from Sennacherib.

The highways lie waste,.... No man walking in them, for fear of the enemy; "the ways of Zion", which are said to "mourn, because none come to the solemn feasts", Lamentations 1:4 none daring to attend the ministry of the word and ordinances; see Isaiah 35:8,
the wayfaring man ceaseth; or, "the traveller rests" (z); or stops; he does not proceed on his journey; a stop is put to a religious course and conversation; there is an entire cessation of religious worship; a sabbath is kept, but not a religious one; he that would walk in Zion's ways is forbid, and is obliged to sit still:
he hath broken the covenant; some, as Kimchi's father, interpret this of the Jews' complaining that God had broken his covenant with them, as in Psalm 89:39 but most of Sennacherib's breaking his covenant with Hezekiah, 2-Kings 18:14 rather this is to be understood of antichrist, whose doctrine is, that faith is not to be kept with heretics, and which will abundantly appear at this distressing time:
he hath despised the cities; as Sennacherib did the fenced cities of Judah; he despised their fortifications, and easily took them, and treated the inhabitants with disdain and contempt; and so will the reformed Protestant cities and countries be invaded, seized upon, and insulted, by the Romish antichrist:
he regardeth no man; so as to keep covenant with them, have compassion on them, and spare them, he fearing neither God nor man.
(z) "cessaverat viator", Junius & Tremellius; "desiit viator", Cocceius.

broken . . . covenant--When Sennacherib invaded Judea, Hezekiah paid him a large sum to leave the land; Sennacherib received the money and yet sent his army against Jerusalem (2-Kings 18:14, 2-Kings 18:17).
despised--make slight of as unable to resist him (Isaiah 10:9; Isaiah 36:19); easily captures them.

The covenant - Sennacherib broke his faith, given to Hezekiah, of departing for a sum of money, 2-Kings 18:14, 2-Kings 18:17. Cities - The defenced cities of Judah, which he contemned, and easily took.