ירמיהו ג:יז מקורות בתלמוד: Avot D'Rabbi Natan

Rabban Shimon ben Gamliel would say: In the future, all the nations and all the kingdoms will gather together in Jerusalem, as it says (Jeremiah 3:17), “And all the nations will assemble there in the name of the Eternal,” and it says (Genesis 1:9), “Let the waters be assembled.” Just as [there the assembly of] all the waters in Creation were in one place, so too, the assembly here is a gathering of all the nations and kingdoms into Jerusalem, as it says, “And all the nations will assemble there.”