Balaam's Oracle on the Kenites and Jethro's Descendants

"Nevertheless Kain shall be wasted (ki im yihyeh le-va'er Kayin)" — for the nations will seek to consume you, and on account of the hatred of Israel, how long will you be able to be saved, until Sennacherib king of Assyria comes and confounds the whole entire world. This is "how long? Asshur shall carry thee away captive (ad mah Asshur tishbeka)." Another interpretation: "Strong is thy dwelling-place (eitan moshavekha)." Balaam said to Jethro: You were with us in Egypt in one counsel, and you ought to have toiled with us, but instead you became a proselyte and cleaved to the seed of Abraham, who is called "Ethan the Ezrahite." "And thou puttest thy nest in a rock (ve-sim ba-sela kinnekha)." Our Sages of blessed memory said: The grandsons of Jethro, they sat in the Chamber of Hewn Stone and taught Torah in public, as it is said, "And the families of the scribes which dwelt at Jabez; the Tirathites, the Shimeathites, the Suchathites" (1 Chronicles 2:55). And "rock" means nothing but the Temple, as it is said, "upon the crag of the rock, and the strong place" (Job 39:28). Another interpretation: "And thou puttest thy nest in a rock." This is the Holy One, blessed be He, who is called "rock," and he came to take shelter under the wings of the Holy One, blessed be He, as it is said, "The Lord is my rock, and my fortress" (2 Samuel 22:2). For were it not so, "nevertheless Kain shall be wasted." And from when does it become liable to be consumed? From when the tribes were exiled; but those who were in Jerusalem were not exiled. And even at the destruction of the Temple, the sons of Jonadab son of Rechab, who were of the sons of the Kenite, were not exiled, for the Holy One, blessed be He, sent them to the mountains of darkness.