מדרש על איוב 12:2

(Ibid. 27) "And Moses sent his father-in-law": R. Yehoshua says: He sent him with gifts. R. Elazar Hamodai says: He sent him with all the honor in the world, as is seen in his (Moses') response to him, as it is written (Numbers 10:30) "I pray you, do not leave us," telling him: You gave us good and beautiful counsel, and the L rd consented to your words. "I pray you, do not leave us." Yithro replied: Is a candle of benefit other than in a place of darkness? Can sun and moon benefit from a candle? You are the sun and Aaron your brother is the moon. What can a candle do between you? Let me go to my land and I will convert all of my countrymen and bring them to the study of Torah and under the wings of the Shechinah. One might think that he went but did not do so. It is, therefore, written (Judges 1:16) "And the children of Keni, the father-in-law of Moses, went up from the city of date-palms," and (Ibid.) "and they went and settled with the people," "the people" signifying "wisdom," (in this instance, Torah study), viz. (Iyyov 12:2) "Truly you are a people, but will wisdom die with you?" Read if not "tamuth" ("die"), but "tumath" ("put to death"). So long as a sage lives, his wisdom endures. When he dies, his wisdom is lost with him. (And thus we find, when R. Yochanan b. Zakkai died, that his wisdom was lost with him.) They went and settled with Yaavetz, it being written of them (I Chronicles 2:55) "the dwellers of Yaavetz." Now were they dwellers of Yaavetz? Rather, they were disciples of (a man called) Yaavetz, viz. "And the families of scribes, 'dwellers' of Yaavetz — Tirathim, Shimathim, Suchathim — These were the Kenites who descended from Chamath, the father of the house of Rechav." "Tirathim" — They sounded the alarm ("mathri'im") and were answered. "Shimathim" — They heard ("shamu") the sound of shofar of Torah at Sinai. "Suchathim" — They dwelt in succoth, viz. (Jeremiah 35:10) "And we (the descendants of Rechav) live in tents, etc."