Here the Prophet in a manner corrects himself, and declares, that though the ruin of Damascus would astonish all, yet it was certain; and so I explain the particle לכן, lacen

It is regarded by the Hebrews as a particle assigning a reason — therefore, for this cause. They then think that a reason is here expressed why God had decreed to destroy that city, even because it had formerly made war with the Israelites, and then with the Jews, and thus it had not ceased to persecute the Church of God. But it is to be taken here in a simpler way, as an affirmative, according to its meaning in many other places. The Prophet then checks here the astonishment which he had expressed, as though he had said, “However this may be, yet it is so appointed by God, though all should be astonished at the destruction of Damascus, yet fall shall its young men, etc.” The meaning is, that no power under heaven was such as could resist God. Then Damascus, as it was devoted to destruction, could not avoid that judgment, though it was, according to the opinion of men, impregnable.

And this passage deserves particular notice, for when hinderances occupy our minds, and are presented to our thoughts, we ought ever to set up this as our shield, “Whatever God has appointed must be fulfilled.” Though, then, heaven and earth may seem united to impede the celestial decree, let us know that we ought to acquiesce in God’s word, and this particle “yet,” or nevertheless, לכן, lacen, ought always to be remembered by us. For we have said that it was Jeremiah’s purpose, in a manner, to bring into subjection whatever men might plan in their own minds; for this alone is sufficient, God has decreed what he declares. It follows, —