What is the Pasuk referring to, when it adds that Yisro brought along Tziporah, "Achar Shiluche'hah"?
Rashi and Rashbam #1: When Hashem told Moshe in Midyan to return to Egypt, 1 he took his wife and his two sons with him and left. However, when he met with Aharon at Har Sinai and told him who they were, Aharon pointed out that it was painful enough for those who were already in Egypt, and that it was unwise to add any more. So Moshe sent them back to Midyan. 2
Ramban #1, Moshav Zekenim, Gur Aryeh (to 18:13): Having recorded earlier (Shemos 4:2) that Moshe took Tziporah and her sons with him to Egypt, it needs to mention here that he sent them back, to clarify how they now found themselves in Midyan. 3
Ramban #2: The Torah is telling us that although Moshe sent them back, Yisro now took them out to reunite them with him, since 'one follows the king wherever he goes.'
Seforno: Yisro first sent Tziporah to find out where Yisrael were encamped. 4
Rashbam #2 and Hadar Zekenim: When Moshe left the inn (after the incident with the angel), he left Tziporah and her two sons there, 5 and went to Egypt on his own. And now, before traveling to the desert, Yisro picked them up and took them with him to reunite them with Moshe, following which 6 he gave her a Nadan 7 (a dowry). 8
Moshav Zekenim: It is after he divorced her with a Get. Why is she still called his wife? Others cannot marry the widow or divorcee of a king (so it is as if she was still married to him). 9
Rashi: See Shemos 4:19 & 20.
Even though the tribe of Levi was exempt from slavery, the risk that they might be included was too great, particularly when we see that they were included in the decree of "Kol ha'Ben ha'Yilod ha'Ye'orah Tashlichu'hu!" (See Oznayim la'Torah).
Seforno: And when she reported back to Yisro that their next stop would be at Har Sinai, where they were destined to serve Hashem (as Hashem had informed Moshe in Shemos 3:12), he delayed his visit, and went out only after they arrived at Har Sinai.
Rashbam: Since the Torah ought otherwise to have informed us there that Moshe sent them back. Hadar Zekenim - Yisro took them back from Egypt to Midyan, to be with him.
Rashbam: Sometimes we find that the word "Achar" means afterwards (see for example Vayikra 15:28.
Rashbam: And we find the word "Shiluchim" meaning a Nadan. See Melachim I 9:16 .
Compare to Shemos 4:20:4:2. It is unclear however, as to why he only gave her a Nadan only now. See also Ibn Ezra.
Moshav Zekenim: Moshe was a Kohen (he served as Kohen during the Milu'im). How was he able to remarry her? He divorced her on condition [that he not return from Mitzrayim]. How was he able to marry a convert? She was less than three years when she converted. (This is like R. Shimon, unlike the other three opinions in Kidushin 78a - PF.)
QUESTIONS ON RASHI
Rashi writes: "'After she had been sent away' - When Hashem told [Moshe] in Midyan, 'Go return to Egypt' (4:19) ... Aharon went out to greet him ... He said, 'Over the original [enslaved people] we are pained... and you are coming to add to them?! [So Moshe] said to her, 'Go to your father's house.'" How can we prove that it was Aharon who gave this advice?
Gur Aryeh #1: Moshe surely sent Tziporah back before reaching Egypt. To do so in Egypt in view of the Bnei Yisrael, would have weakened their resolve, causing them to despair of the Redemption. Nor did Moshe decide to so on his own; for if he initially decided to take his wife and children along, what would have changed his mind? The only person who met Moshe on the way was Aharon.
Gur Aryeh #2: We would not say that Moshe accepted such advice, from anyone lesser than he; it could only have been from his older brother Aharon.
Rashi writes: "Aharon said, 'Over the original [enslaved people] we are pained....'" But Rashi (to Shemos 5:4) wrote that the Tribe of Levi was not enslaved?
Gur Aryeh: Even so, they (i.e. even the tribe of Levi) remained in fear of the Egyptians' evil decrees, such as "any boy that is born, cast him into the Nile"(1:22); and their slaughtering 150 children for Pharaoh every morning and evening (see Rashi to 2:23).
