A simple understanding of the crossing of the Yam Suf would be that this body of water was in between Egypt and Eretz Yisroel (and/or Mt. Sinai), and had to be crossed — from one side to the other side — in order to get from one to the other. (That the Yam Suf is the Red Sea is indisputable, even if some try to suggest otherwise. Suffice it to say that the Yam Suf is given as an eastern boundary of Eretz Yisroel (Shemos 23:31; see Melachim I 9:26 and Rashi on Shemos 10:19), referring to the eastern fork of the Red Sea, i.e. the Gulf of Aqaba. We crossed the Gulf of Suez (the western fork), as evidenced by our coming out in מדבר שור (Shemos 15:22), which “faces Egypt” (Bereishis 25:18), southwest of Eretz Yisroel.) Several Rishonim (early commentators) are of the opinion that we never crossed the Yam Suf from end to end, but came out on the same side we entered, traveling in a semicircle (or three sides of a rectangle). And there were valid reasons why they thought so.
The Talmud (Arachin 15a) says that the Children of Israel were concerned that just as they had emerged from the sea on this side, the Egyptians had emerged (alive) on the other side, and could continue to chase them. Tosfos asks why they were concerned, since the Egyptians were stuck on the other side! Did they think God would perform a miracle for the Egyptians too, so that they could cross the sea? Additionally, several stops after crossing the sea, the Children of Israel were back at the Yam Suf (Bamidbar 33:10). Why did they go back to the sea they had just crossed?
To answer these questions, Tosfos suggests that the Yam Suf was south of both Eretz Yisroel and Egypt (and not between the two), and went from the west (near Egypt) to the east (south of Edom and Moav). The Children of Israel entered the sea on its northern side (near Egypt) and emerged on the same side farther east. They were concerned that the Egyptians had emerged elsewhere on the northern side of the sea, so could still chase them. As they traveled farther east — parallel to the sea on its northern side — they ended up on the coast once again. (Tosfos actually includes a map. However, the map is not the same in all editions of the Talmud; even the same publishers have “updated” the map over the years.)
Ibn Ezra (Shemos 14:17), Chizkuni (Shemos 14:22) and Radak (Tehillim 136:13, see also Shoftim 11:16), point out that we were in מדבר אתם before we crossed the sea (Shemos 13:20 and Bamidbar 33:6) and after we crossed it (Bamidbar 33:8; please note that מדבר אתם and מדבר שור are one and the same, see Ibn Ezra on Shemos 15:22). How could we have been in the same desert both before and after crossing the sea? Well, if we entered and exited on the same side, this is not an issue.
(We can add Rambam (Avos 5:4) to the list of Rishonim who say we crossed the Yam Suf in a semicircle rather than from end to end, but keep in mind that he wrote his commentary on the Mishna earlier in his life, before he moved to Israel and then Egypt, so might have changed his mind.)
Despite these strong arguments, because we now know that the Yam Suf surrounds the Sinai Peninsula, there’s no need to say we didn’t cross it. [Bear in mind that G-d instructed us to make an about face (Shemos 14:2), going back to where we had previously been, in order to trick Pharaoh (14:3).] Our route can now be explained very simply: we traveled east past the northern tip of the Gulf of Suez (between the gulf and the Great Bitter Lake) into מדבר אתם before turning around, traveling west back to the northern tip of the Gulf of Suez (or beyond it), where we became “trapped” between the Egyptians and the Yam Suf. After crossing the sea — back to the eastern bank of the Gulf of Suez — we were in מדבר אתם once again, but concerned that the Egyptians may have emerged where they had entered and could still chase us by traveling north of the gulf (as we had previously done). As far as why we were back at the Yam Suf a few stops later, we traveled south along the eastern coast of the Gulf of Suez to get to Mt. Sinai, which is in the southern part of the Sinai Peninsula, or — for those who think Mt. Sinai is in Saudi Arabia — traveled across the Sinai Peninsula to the Gulf of Aqaba before moving past it.
You may have noticed that I suggested we return to the northern tip of the Gulf of Suez, rather than to the western side of the gulf; allow me to explain why. We were camped by Pi Hachiros before entering the sea (Bamidbar 33:8), called “Pi Hachiros” because it was the gateway to freedom for those trying to escape from Egypt (Midrash Lekach Tov and Midrash Seichel Tov). It makes more sense for this “gateway to freedom” to be north of the gulf; if it was on its western bank, one would still need to go around the northern tip before being free. (It would also explain why the deity located there was called “Baal Tz’fon” — the Baal (deity) of the north — as it was near the northernmost part of the gulf.) Since we were camped “before Pi Hachiros,” we would have been on the shore of the northern tip of the Gulf of Suez, and crossed the sea from the north to the east (diagonally, moving southeast), emerging back at מדבר אתם. Please note, though, that even if we went back to the western bank of the Gulf of Suez, the issues raised by the Rishonim have still been fully addressed, and we could have crossed the Yam Suf from one side to the other side.
Rabbi Dov Kramer is convinced that Midbar Shur is referred to as the desert of Eisam in order to highlight the fact that we were on the eastern side of the Gulf of Suez both before we crossed the Yam Suf and after we crossed it.
