4 Ezra 13:32-40: "And they shall plan to make war against one another, city against city, place against place, people against people, and kingdom against kingdom. And when these things come to pass and the signs occur which I showed you before, then my Son will be revealed, whom you saw as a man coming up from the sea. And when all the nations hear his voice, every man shall leave his own land and the warfare that they have against one another, and an innumerable multitude shall be gathered together, as you saw, desiring to come and conquer him. But he will stand on the top of Mount Zion. And Zion will come and be made manifest to all people, prepared and built ... and he will reprove the assembled nations for their ungodliness.... And as for your seeing him gather to himself another multitude that was peaceable, these are the ten tribes which were led away from their own land into captivity in the days of King Hoshea, whom Shalmaneser the king of the Assyrians led captive; he took them across the river, and they were taken into another land".
For simple comparison here the first century 4 Ezra (likely using even older Jewish source) uses similar symbolism of a multitude from 10 lost tribes of Israel.