Midrasch zu Schemot 22:2

(Bamidbar 10:30) "And he said: I pray ("na") you, do not leave us." "Na" is a term of imploration. He said to him: If you do not take it upon yourself (to remain with us), I decree it upon you. For now, (if you leave,) Israel will say: Yithro became a proselyte not out of love, but only in expectation of a portion in the land, which, seeing not to be forthcoming, he abandoned us. Variantly: (Moses said to him:) You think you are increasing G-d's honor (by planning to make conversions in your land.) You are only diminishing it! How many (prospective) proselytes would take shelter under the wings of the Shechinah (if you remained.) But now, you are closing the door against them. They will say: If Yithro, the father-in-law of the king, did not take it upon himself (to remain with Israel), how much more so, we! "inasmuch as you have known our camping ('chanothenu') in the desert": Moses said to him: If another, who had not seen the miracles and wonders wrought for us in the desert, up and left, it might befit him, but you, who have seen them, can you do so? R. Yehudah says you who saw the "chein" ("favor" [a homiletic reading of "chanothenu"]) bestowed upon our fathers in Egypt, viz. (Shemot 12:36) "And the L-rd placed the favor of the people in the eyes of Egypt," would you pick up and leave? "and you have been 'eyes' for us": And not that alone, but in all things that were concealed from our eyes, you enlightened us, viz. (Ibid. 18:21) "And you shall see from all the people, etc." Now were these things (of appointing judges) not known to Moses from Sinai, viz. (Ibid. 23) "If you do this thing and G-d commands you, then you will be able to bear up"? And why did they escape Moses? To credit the thing to Yithro. Variantly ("and you have been 'eyes' for us"): that he (the proselyte) be as beloved by us as the apple of our eye, viz. (Devarim 10:19) "And you shall love the stranger," (Shemot 22:2) "And a stranger you shall not taunt and you shall not oppress."

(Devarim 22:17) "And they shall spread the garment before the elders of the city": They must clarify the matter as a (new) garment. The witnesses for both husband and father must clarify the matter before the elders of the city. This is one of the things that R. Yishmael was wont to expound as a mashal (a metaphor). Similarly, (Shemoth 22:2) "If the sun shone upon him": Now is it upon him alone that the sun shines? What, then, is the intent of "If the sun shone upon him"? Just as the sun is "peace" for the world, here, too, if he (the one threatened with robbery) knows that he (the robber) is "at peace" with him (and will not kill him if he resists, [as in the instance of a father robbing a son]) and he (the son) kills him, he is liable (for murder). Similarly, (Ibid. 21:19) "If he arise and walk outside on his crutch" — on his own power.