Charles Spurgeon Commentary Jeremiah 32:12-14

"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." — Jeremiah 32:12-14 (ASV)

And I gave the evidence of the purchase to Baruch the son of Neriah, the son of Maaseiah, in the sight of Hanameel my uncle's son, and in the presence of the witnesses that subscribed the book of the purchase, before all the Jews that sat in the court of the prison. And I charged Baruch before them, saying, Thus says the LORD of hosts, the God of Israel; take these evidences, this evidence of the purchase, both which is sealed, and this evidence which is open; and put them in an earthen vessel, that they may continue many days.

They had no iron safes in those days; so their practice was to put their documents into earthen vessels, and bury them deep in the earth, where they believed they would be secure.