This is definitely one of the most well known verse in the Bible, and rightfully so, for it is a message of hope.
The caution, of course, is not to mistake this as a message of prosperity or a life of ease. In fact, in this verse, the Lord is speaking to the Israelites who are in exile. And He told them they would continue to be in exile for 70 years. That's the background of this promise. He wasn't telling them they were about to be rescued any time soon. He was telling them that the exile was going to last a long time, but that He still had a plan, He was still in control, and His plans are for our good and for His glory.
Though this promise was specifically for the exiled Israelites, it does still hold true for us today. And we can grab onto that same hope. No matter how bad your circumstances, and no matter how long they will last, God is still in control, He still has a plan, He is still good, His plans for you are good (thought maybe not the ones you would choose for yourself) and for His glory.
Tomorrow's Bible In a Year Passage: Jeremiah 30:1-31:26, 1 Timothy 2:1-15, Psalm 87:1-7, Proverbs 25:18-19