Charles Spurgeon Commentary Jeremiah 30:18-19

"Thus saith Jehovah: Behold, I will turn again the captivity of Jacob`s tents, and have compassion on his dwelling-places; and the city shall be builded upon its own hill, and the palace shall be inhabited after its own manner. And out of them shall proceed thanksgiving and the voice of them that make merry: and I will multiply them, and they shall not be few; I will also glorify them, and they shall not be small." — Jeremiah 30:18-19 (ASV)

Well might the Lord introduce such a promise as this with the word, "Behold." Again I remind you that these are the people who had their hands on their loins; these are the ones who were in great trouble of soul, yet now they are merry, and full of gladness; and we also have learned to sing:

My mourning he to dancing turns,
For sackcloth, joy he gives,
A moment, Lord, your anger burns,
But long your favor lives.