One of the issues discussed regarding the exodus from Egypt contrasts the original request made of Pharaoh — to let the Jewish people go on a three-day journey to bring offerings to G-d (Sh’mos 5:3), with what they actually did — leaving and never returning. As Rav Yaakov Kamenetsky z”l asks (3:18), since G-d’s signature is truth, how could He misrepresent His intentions? To summarize Rav Yaakov’s approach, the request was really for a temporary break from the hard labor in order to reconnect with G-d, which would have allowed them to survive (spiritually) for the remainder of what would have been a 400-year exile in Egypt (see B’reishis 15:13). Because Pharaoh refused, G-d had to end the exile early (after only 210 years in Egypt, which was 400 years after Avraham’s son Yitzchok was born) so that the nation wouldn’t undergo any further spiritual deterioration.
Rabbeinu Bachye brings a similar, although a profoundly different approach, suggesting that the reason for an initial three day retreat would have been to provide the nation with their first exposure to G-d’s commandments, as giving them the whole Torah right away would have been too much for them to handle. In fact, G-d did give them several commandments (at Marah), weeks prior to the public revelation at Sinai (see Rashi on Sh’mos 15:25). The implication is that shortly after returning from this initial spiritual retreat they would have left Egypt completely (whereas Rav Yaakov is suggesting that they would have stayed for another 190 years, and a different generation would have come out). Either way, since had Pharaoh agreed to let the nation go on a three-day spiritual retreat they would have returned to Egypt, the request itself was completely above board.
Rabbeinu Bachye’s approach has the advantage of not having to explain how Moshe could have been told that G-d would take the nation out of Egypt and bring them to the Promised Land (and other similar statements that clearly indicate that G-d had planned to take them out of Egypt completely, see 3:8, 3:10, 3:17, 6:1, 6:6, 6:26 and 7:2), as Moshe was told what his entire mission would encompass, not just the first part. Nevertheless, it is evident that G-d was telling Moshe things that were going to happen, including that Pharaoh would initially refuse (3:19), that G-d would harden Pharaoh’s heart so that he wouldn’t listen (7:3-4), and even that Pharaoh would ask for a “sign” (7:9). As far as the original request, though, Moshe being told that God would (eventually) take them out of Egypt completely does not negate the possibility that the original request for a three-day journey was an up-front one that Pharaoh could have accepted (but didn’t). According to Rav Yaakov’s approach, on the other hand, had Pharaoh agreed to the original request, it would have been almost two centuries before the nation left Egypt for good. Even so, since the purpose of the three-day retreat was to allow the nation to be worthy of redemption 190 years later, talking about that eventual exodus now does not contradict the notion that the original request for a short-term leave was legitimate.
Assuming that the nation would have returned to Egypt after their spiritual retreat had Pharaoh agreed to it, why (and when) did it change to a demand that Pharaoh let them go completely? When he finally gives in, why must it be forever, and not for the originally requested three-day journey that would have been followed by a return to Egypt? Rav Yaakov himself explains Pharaoh’s change of hear and trying to bring the nation back (14:5) as regretting that he let them go completely rather than just granting them a temporary leave. Why couldn’t the nation reconnect with G-d (or get their first mitzvos) at that point and then return to Egypt until the time was right to leave?
Up to the very end, the discussion between Pharaoh and Moshe was about the details of the requested three-day journey. G-d’s continually commanded Pharaoh to “send out My people so that they can serve Me” (7:16, 7:27, 8:16, 9:1 and 9:13), not “let My people go free.” In his request to remove the frogs (8:4), Pharaoh says he will “send the nation out [so that] they can bring offerings to G-d,” but doesn’t offer to free them. When he offers to let them bring offerings to G-d in Egypt itself (8:21), Moshe says that they must travel three days out of Egypt before doing so (8:23), not that their leaving Egypt so there’s no reason to do so in Egypt before they leave. After being warned about the forthcoming plague of locusts, Pharaoh offers to let the adults go, but not the children (10:11), while Moshe insists that the children must also take part in the celebration. After the plague of darkness, Pharaoh says that everyone can go, except the livestock, which they must leave behind (10:24). Moshe’s response was that they must bring all the livestock too, because they have no way of knowing how many offerings will need to be brought (or from which kinds of animals). If the three-day offer was off the table, Moshe’s shouldn’t have given reasons why everyone and everything must take part in the spiritual retreat. Instead, he should just tell Pharaoh something like, “hey, don’t you get it? We’re not coming back! G-d’s gonna hit you harder and harder, so just give up!” There must have still been a possibility that they would only leave temporarily, even at this late stage. Why did it change after that? And if going on a spiritual retreat was still appropriate, why didn’t it happen?
Another, related, issue is that the nation was told that they would be freed (completely) before any of the plagues started (6:6-8). It’s one thing for Moshe to be informed that Pharaoh would be stubborn and they will therefore eventually be set free, but how could the whole nation be told that they will be free if it was still theoretically possible for Pharaoh to still accept the three-day offer?
Sh’mos Rabbah (3:8 and 11:3) tells us that the reason G-d had Moshe ask Pharaoh to allow the nation to go on a three-day journey rather demanding that they be freed forever was to mislead the Egyptians. Since they thought they were only allowing the nation to leave temporarily, when they would realize that the nation was not returning they would chase after them and eventually drown in the sea (as a punishment for drowning the nation’s babies). If, on the other hand, when they finally gave in they knew it meant letting the nation go forever, there would be no reason to chase after them when they didn’t return.
While this would seem to contradict Rav Yaakov’s (and Rabbeinu Bachye’s) premise that G-d did initially intend on it being a temporary retreat, I would suggest that it does not. When Moshe first went to Pharaoh, at the end of Nissan 2447 (see Rabbeinu Bachye on 10:5) or in Iyar 2447 (see Rav Saadya Gaon on 7:15 and Midrash Seichel Tov 7:25), had Pharaoh said yes, it really would have only been temporarily. However, once he refused, that offer was no longer on the table. It would now take the power of the plagues to change Pharaoh’s mind, and those plagues were reserved for the exodus (see B’chor Shor on 6:6). They would be an everlasting testament to G-d’s involvement in our mundane world (see Ramban at the end of our Parasha), and would be part of our yearly retelling of the exodus story, and were not going to be employed just to get Pharaoh to agree to a temporary leave. Nevertheless, in order to mislead the Egyptians, when Moshe went back to Pharaoh again three months later, he never informed him that the request had changed. The wording he used was ambiguous enough to leave the impression that it was the same, while still being fully accurate. After all, they would travel for three days to serve G-d at Mt. Sinai (see Ralbag and Chizkuni on 3:18)! And Moshe never said they wouldn’t stay longer, or that they would return (see Matanos K’huna on Sh’mos Rabbah 3:8).
Moshe was able to respond to Pharaoh’s questions in a way that was truthful without being completely forthcoming. Even though the nation would have returned to Egypt had Pharaoh accepted the initial offer the first time, he and his people were purposely misled into thinking that this offer was still available until the very end, in order to complete the punishment of the Egyptians by drowning them in the Sea of Reeds.