Why did Moshe see fit to beseech Yisro not to leave them, when he begged him "Al Na Ta'azov osanu"?
Rashi: So that people should not say that Yisro only converted in order to receive a portion in Eretz Yisrael, and now that he discovered that he would not receive one, he left them.
Seforno: Moshe was asking Yisro at least to let his sons accompany them.
What did Moshe mean when he said to Yisro "Ki Al Ken Yadata Chanosenu ba'Midbar"?
Rashi: He was telling him that, since 1 he (Yisro) was acquainted with all their travels in the desert, it would be appropriate for him to remain with them and not to abandon them.
Seforno: Having seen up close Hashem's relationship with Yisrael, if he severs connections with Yisrael completely, 2 he will create a Chilul Hashem, inasmuch as people will say that had he seen true G-dliness, he would not have abandoned them together with his children.
Rashbam: He meant to say that Yisro took to heart their camping in the desert and acted as their advisor as the Pasuk describes at the beginning of Yisro. 3
Da'as Zekenim, Hadar Zekenim: Since you saw the miracles and mighty deeds that Hashem performed with Yisrael, if you stay with us, people will say that surely he abandoned his land and inheritance because he saw the greatness of Hashem and the good He did to His nation.
What did he mean when he concluded "v'Hayisa lanu le'Einayim"?
Rashi #1 (citing Targum Onkelos): With reference to the previous phrase, it means that he had seen with his own eyes the miracles and mighty deeds that Hashem performed with Yisrael.
Rashi #2: Whatever will be hidden from us, you will enlighten our eyes (advise us). 1
Rashi #3: He meant that if he remained with them, he would be dear to them like their eyes. 2
Refer to 10:31:2:4.
Rashi writes '
Moshav Zekenim: "V'Heitavnu Lach" implies that [Yisro would receive Doshnah of Yericho] for Tovas Hana'ah (mere rights to use it until the Mikdash will be built), but not absolutely, and [people will say that] therefore, he left.