for it is God who works in you to will and to act according to his good purpose
What's the most quoted part of Jeremiah? Probably that verse from chapter 29, you know the one... I know the plans I have for you, plans to prosper you and not to harm you, plans to give you a future and a hope.
Such words slip of the tongue so easily until the day you come up against something that robs you of hope, turns the future bleak or takes away your sense of being prospered. Of course what neither Paul nor Jeremiah are trying to do is to give us some false sense of security or spin current current circumstances to make things easier. Neither are they suggesting that we will not suffer in any way and that we will all be wealthy.
Our future rests in our hope, and our hope is in Christ. Both Paul and Jeremiah would point us towards our eternal futures and not the immediate future of the next year or the next ten years or even the next twenty years.