The coasts of the earth - See Jeremiah 6:22 note.
Thither - Really, here. Not to the north country, but to Palestine, where Jeremiah wrote. A company is the word constantly used of Israel at the Exodus Exodus 16:3 as an organized community.
Related Commentaries of Jeremiah 31:8
Jeremiah 31:8
8 Behold, I will bring them from the north country, and gather them from the coasts of the earth, and with them the blind and the lame, the woman with child and her that travaileth with child together: a great company shall return thither.