John Calvin Commentary Jeremiah 50:27

"Slay all her bullocks; let them go down to the slaughter: woe unto them! for their day is come, the time of their visitation." — Jeremiah 50:27 (ASV)

He continues with the same subject; he commands the Persians and the Medes to slay every strong man in Chaldea. For by bullocks, he undoubtedly means, metaphorically, all those who excelled in strength, power, or wealth. In summary, what he says is that the vengeance he now speaks of would be directed not only against the common people but also against the highest and most prominent among them. He therefore includes the nobles as well as all the men of war, for he refers not only to physical strength but also to power and authority.

Slay, then, he says, all her bullocks; that is, whatever is most valued in Chaldea. This was to perish when the day of vengeance came. He afterwards says, let them descend to the slaughter. We must always remember what I have said: that the Prophet gave orders as if he had the Medes and Persians under his direct command and authority, because the whole world is subject to God’s word.

He says, Woe to them! for their day is come, and the time of their visitation. This was added because the faithful might have wondered among themselves and said, “How can it be that Babylon should perish so quickly?” For God had seemed to favor that monarchy for a long time, as if he intended to protect it forever.

Hence, the Prophet speaks here of the time of visitation, so that the faithful might not doubt this prophecy, because God had not yet put forth his hand. He then reminded them that God has his fixed times and that he does not visit nations every day—that is, he does not execute his judgments every moment, but at the time which he has appointed.

Whenever, then, the ungodly confidently exult and triumph, let us always remember this truth: that the time has not yet come for God to execute his judgment. Why is this? Because there is a fixed time of visitation, and that depends on God’s will. Let us then learn to bear patiently all our trials until it pleases God to show that he is the judge of the world. It follows—