They journeyed from Rameses in the first month, on the fifteenth day of the first month; on the day after the Pesach offering the Children of Israel went forth with an upraised hand, before the eyes of all the Egyptians. And the Egyptians were burying those among them whom Hashem had struck, every firstborn; and on their gods, Hashem had inflicted punishments.
The Passuk implies that the reason why the Jewish People delayed their departure from Egypt and did not leave that night immediately after the firstborns were stricken by the plague, rather waited until the morning, was so that they would 'go forth with an upraised hand before the eyes of all the Egyptians'. This is hard to understand; since it was from Egypt that the Jews were leaving, it would have been just the same 'before the eyes of all the Egyptians' had they left immediately that night.
Moreover, delaying their departure until the morning when the plague was essentially over carried a significant risk, for by doing so there was a great chance that by then the hearts of the Egyptians would harden, and they would once again go back on their word and not let the Jews leave Egypt. This would not be so had they departed during the night in the heat of the plague, during those initial intense moments of the Egyptian's mourning, as at that time the Egyptians would not have had the presence of mind to come down strong on the Jews to prevent their exodus. Additionally, it seems that all that the Torah is attempting to relate in this Parsha is the fact that the Jewish People left Egypt; what does that have to do with what the Passuk goes on to tell us, that the Egyptians were burying their dead, and that Hashem inflicted punishments upon their gods as well?
Rabbeinu Bechaya asks another question on these Passukim. The Passuk says, 'And the Egyptians were burying those among them whom Hashem had struck, every firstborn; and on their gods, Hashem had inflicted punishments'. What does the Egyptians burying their dead have to do with the fact that Hashem struck their idols?
He answers that what had actually occurred, was that at the very same moment of midnight, the firstborns died and the idols were struck. Nevertheless, the Egyptians were so engulfed in mourning over the death of their firstborns, that they didn't even realize what had occurred to their idols. It was only the next morning when they came to their places of worship to arrange the funerals for their dead, that they saw what had happened to their idols. Thus, as the Passuk relates, only when the Egyptians were burying their dead, did they realize that their gods, too, had been hit.
In light of Rabbeinu Bechaya's notion - that although their idols were also struck at midnight, the Egyptians did not comprehend it until the morning - we can understand why Hashem did not want the Jews to leave until the morning. The reason being, because Hashem wanted the Egyptians to fully grasp the severity of the last plague while the Jews were still in Egypt, for only then would it be a complete fulfillment of 'the Children of Israel going forth with an upraised hand, before the eyes of all the Egyptians', and this only occurred in the morning when the Egyptians saw their idols smitten.
We can also understand why there was no reason to be concerned that once morning came, and the plague would essentially be over, the Egyptians might go back on their words. For once morning came, the Egyptians were again thrown back into the intensity of the plague, when they realized that their idols had been hit, and once again they would not have the heart to prevent the Jews from leaving.
And finally, we can understand the juxtaposition between the Jewish People leaving Egypt, and the Egyptians burying their dead and their idols being stricken. For the timing that was deemed right for the Jews to leave Egypt, was very much dependent upon the Egyptians realizing that their idols had been inflicted as well, which only happened when they began burying their dead.
זרע שמשון פרשת מסעי אות א
