Thomas Aquinas Commentary Jeremiah 32:12-15

"and I delivered the deed of the purchase unto Baruch the son of Neriah, the son of Mahseiah, in the presence of Hanamel mine uncle`s [son], and in the presence of the witnesses that subscribed the deed of the purchase, before all the Jews that sat in the court of the guard. And I charged Baruch before them, saying, Thus saith Jehovah of hosts, the God of Israel: Take these deeds, this deed of the purchase which is sealed, and this deed which is open, and put them in an earthen vessel; that they may continue many days. For thus saith Jehovah of hosts, the God of Israel: Houses and fields and vineyards shall yet again be bought in this land." — Jeremiah 32:12-15 (ASV)

Here is the interpretation of the purchase.

1. He hands over the deed: in the eyes of all the Jews who sat in the courtyard of the prison, who had come to console and to consult, because the matter pertained to everyone.
2. Their diligent care is noted: and I instructed Baruch before them, saying, “Thus says the Lord of hosts, the God of Israel: Take these books, the sealed deed of purchase, and this book which is open,” that is, not sealed, so that when they send it, it may be viewed. I have been represented in the hands of the prophets (Hosea 12:10).
3. They are consigned to safekeeping: and put them in a clay jar.

Thus says the Lord. This is what Jeremiah said above: that he understood the word of the Lord. The vineyard shall give its fruit, and the earth its growth, and the heaven shall give its dew (Zechariah 8:12).