John Calvin Commentary Jeremiah 49:26

"Therefore her young men shall fall in her streets, and all the men of war shall be brought to silence in that day, saith Jehovah of hosts." — Jeremiah 49:26 (ASV)

Here the Prophet, in a way, 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 reason. They then think that a reason is expressed here why God had decreed to destroy that city, namely, because it had formerly made war with the Israelites, and then with the Jews, and thus had not ceased to persecute the Church of God. But it is to be understood here in a simpler way, as an affirmative, according to its meaning in many other places.

The Prophet then checks here the astonishment he had expressed, as if 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 could resist God. Thus Damascus, since it was devoted to destruction, could not avoid that judgment, even though, according to human opinion, it was impregnable.

And this passage deserves special attention, for when hindrances occupy our minds and present themselves to our thoughts, we should always set this up as our shield: “Whatever God has appointed must be fulfilled.”

So, even if heaven and earth may seem united to impede the celestial decree, we must realize that we ought to acquiesce in God’s word, and we should always remember this particle “yet,” or “nevertheless,” לכן, lacen. For we have said that it was Jeremiah’s purpose, in a way, to bring into submission whatever people might devise in their own minds, for this alone is sufficient: God has decreed what he declares.