The Babylonian army is besieging Jerusalem. Because he had prophesied that Babylon would conquer Jerusalem, Jeremiah is being held in confinement by King Zedekiah.
He personally is imprisoned. His nation is under siege. What should he do now? What future can he expect? Should he just give up? Should he just give in to despair? What should he do?
Jeremiah receives a message from the Lord. He is told to use his right of redemption to buy his uncle's field.
The whole country is soon going to be under the control of Babylon. Yet, the Lord directs him to actions that assume that there will be a future. The future won't be there right away. "Buy the field and put the deeds in a place where they'll be safe for a long time.
Jeremiah is sustained by the history of what already has happened to his people, how the Lord had led them out of slavery in Egypt and protected them through their long journey to the promised land. He also remembers that the people responded with disobedience and concludes that they deserve the bad thing that is happening to them now.
But the Lord who has delivered them before will once again be their deliverer. Jeremiah prays:
Yet you, O Lord God, have said to me, "Buy the field for money and get witnesses"--through the city has been given into the hands of the Chaldeans."