V 1.
Jeremiah sent a letter from Jerusalem to the remaining elders among the exiles, to the priests and prophets, and to all the people whom Nebuchadrezzar had deported from Jerusalem to Babylon,

Jeremiah was the prophet of Judah and knew that he had responsibility for God's people whether they were at home in their own land or exiled in Babylon.  Jeremiah took his responsibility seriously and that the people in exile were being bombarded by false prophets who were telling them they'd soon be home again - giving false hope.  Jeremiah knew those prophesies weren't true, so he wrote to the people in exile, seeing he couldn't be there himself.

Sometimes continuing to do the work God has given is not easy.  There are barriers and difficulties we must face.  We can give up the job; we can allow ourselves to become satisfied with a job half-done; or we can find a way to get it done, as Jeremiah did.

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V 4
This is what he wrote: These are the words of the Lord of Hosts the God of Israel: To all the exiles whom I have carried off from Jerusalem to Babylon:
NLT.  The Lord Almighty, the God of Israel, sends this message to all the captives he has exiled to Babylon from Jerusalem

Jeremiah was careful to make sure they would know that, even though he was now writing a letter to them, the exiles would still be sure it was God's message he was sending, not his own opinions.  He was also careful to stress that it was through God's action that they were in exile - as they had been warned would happen if they continued to ignore God's messages.

Vs 5, 6
Build houses and live in them; plant gardens and eat their produce. Marry wives and beget sons and daughters; take wives for your sons and give your daughters to husbands, so that they may bear sons and daughters and you may increase there and not dwindle away.

Even though they were away from their own country and would be for a long time, God wanted the people to know he still cared about them and wanted them to live lives as normal as possible. He still wanted them to thrive, even in a foreign land.  This was a message of hope for the exiled people.

Building homes and planting gardens was a sign that the people were prepared to settle there for as long as was necessary and to make the best of their situation.  Continuing to marry and have children meant that it was still important to be God's people and to remember that there would be a future for them, even if it was some years away.  This required a practical expression of faith in God.

V 7
Seek the welfare of any city to which I have carried you off, and pray to the Lord for it; on its welfare your welfare will depend.
NLT.  Work for the peace and prosperity of Babylon.  Pray to the Lord for that city where you are held captive, for if Babylon has peace, so will you.

God wanted his people to accept that they were captives and would be for a long time to come.  He not only wanted them to accept passively but to actively work for the good of the country they found themselves in, so that their own welfare would be looked after.  They needed to learn that they were where they were because it was God's plan, and it was also God's plan that they be cared for properly in that situation.  They must learn to trust that his plans were right and to trust in his care fore them wherever they might live.

Quest Study Bible. p 1084.  We must remember that God sent Judah into exile.  His will was that Babylon defeat the people of Judah, not just to punish them, but so they would leaarn once again tpo submit to his will.  Learning to pray for teh peace and prosperity of their conquerors was one of their first lessons.  Furthermore, the Jews were to bring their faith in God to this strange nation.  Perhaps they could influence their captors to serrve the Lord as well.  Since they would be captive for 70 years, it was also wise to pray for peace so they might enjoy their lives.

We don't always find ourselves in situations that are tolerant of our Christian beliefs. Perhaps this is also a message for us to make the best of whatever situation we find ourselves in and to pray for those we associate with, whether Christian or not.

Vs 8, 9.
for these are the words of the Lord of Hosts the God of Israel: Do not be deceived by the prophets or the diviners among you, and do not listen to the wise women whom you set to dream dreams. They prophesy falsely to you in my name; I did not send them.  This is the very word of the Lord.

Jeremiah wanted  the people in Babylon to be able to tell the difference between the true message from God which he brought to them and the false prophesies and dreams of prophet and mediums who were in Babylon with them and raising false hopes.

New Bible Commentary p 694.  The story illustrates neatly the difference between the Lord's thinking and human plans.  What seems to be the end of hope is but the end of tawdry dreams; with God there is always a real future.  In it, there is willing and joyful communication with him, no longer hidden by human self-seeking.  Not is this future in some unreal 'spiritual' realm. It exists within normal life; hence the marrying and the houses, and - in time - the returning to the ancient land (v 14)