John Calvin Commentary Jeremiah 31:27

"Behold, the days come, saith Jehovah, that I will sow the house of Israel and the house of Judah with the seed of man, and with the seed of beast." — Jeremiah 31:27 (ASV)

We see that the Prophet brings forward nothing new, but only inspires the Jews with confidence regarding their deliverance and their return. He also employs another analogy, namely that God would again sow Judah in the land, so that he might produce an increase of people, and also of cattle, and of all kinds of animals. We have said that the land was to be dreary and forsaken for a time. Since God then condemned the land in this way, as it were, so that all might regard it as given up to desolation and solitude, the Prophet says that God would cause it to be inhabited again by both people and beasts.

But the analogy reveals God's favor even more fully. A contrast is to be understood between a cultivated and a deserted land. It is as if someone were to say, “They will sow and reap on mountains where grain has never grown, where a plow has never been seen.” If anyone were then to promise a sowing and a harvest in a desert land, it would be something new and could hardly be believed.

In the same way, the Prophet now says, I will sow, etc., as if he said, “The land indeed will be accursed for a time, so that it will not sustain either people or beasts; but it will be sown again.” I will sow it, he says, with the seed both of people and of animals. And in this way he addresses a question that might have been asked, “How can it be that the land will be inhabited again, since it is now deserted by its inhabitants?” Precisely because God will sow it. In this way, then, the Prophet answers the question. But at the same time he exalts God's favor, as if he had said that there would be no other remedy for the land's barrenness until God himself should cultivate it and scatter seed on it. This is the same as saying that the restoration of the land would not be the work of human industry or power, but of the wonderful power of God.