Two unusual features distinguish the tenth plague—the smiting of the Egyptian firstborn—from the other nine that G‑d brought against the Egyptians. Firstly, Moses announced the specific time that it would take place (“about midnight”), and secondly, the Israelites themselves were commanded to take precautions against the plague afflicting them—they were to stay indoors, and set a sign, in blood, on their doorposts. The Rebbe explains why these features were attached only to this plague, and how they indicate to us the path that we must follow to bring about the redemption of the future—the Messianic Age.

1. The Time and the Precautions

When Moses announced to Pharaoh the coming of the final plague, the smiting of the firstborn, he mentioned the time that it would occur. G‑d had said that it would take place at midnight. Moses said that it would be at “about midnight,”1 fearing that Pharaoh’s astrologers might make a mistake in their calculations of the precise fixing of midnight and might accuse him of inaccuracy.2 Nonetheless, this raises a difficulty. Why was the timing of the plague mentioned at all? The mere warning of its imminence would surely have been sufficient, as it was in the case of the other nine plagues. We are forced to conclude that there is a special and significant connection between the plague of smiting the firstborn and the time of midnight, so that in mentioning one, Moses had to mention the other.

In two further ways, the tenth plague was unique.

Firstly, the Jews had to make a special sign “on the two doorposts and the lintel”3 of their houses, a sign in the blood of circumcision and of the Paschal lamb,4 so that the plague would not be visited on them.

Secondly, they had to remain indoors throughout the night: “And none of you shall go out from the entrance of his house until the morning,” because “once the force of destruction is given permission (to unleash itself) it makes no distinction between the righteous and the wicked.”5

But why should these provisions have been necessary? The previous plagues had been directed solely against the Egyptians, without the Israelites needing to take any special precautions to preserve their immunity. Why was the tenth plague different in this respect? And why were two precautions (the sign of the blood, and the confinement to their houses) needed?

2. The Uniqueness of the Final Plague

We can approach an answer by first understanding that the other nine plagues were not of the kind whereby “the force of destruction is given permission (to unleash itself).” They were limited to a specific manner and extent of damage. The hail, for example, destroyed “the flax and the barley… but the wheat and the spelt were not smitten because they were not grown up.”6 But the smiting of the firstborn was not limited to any specific manner of destruction; the force which “makes no distinction between the righteous and the wicked” was set loose—and therefore the Israelites had to guard themselves against it.

At a deeper level, the smiting of the firstborn was unique in its purpose, not only in its manner. The other plagues were not primarily to destroy, but to create in the Egyptians an awareness of G‑d: “In this you shall know that I am the L-rd.”7 And this was not a lesson that needed to be enforced amongst the Israelites, who already acknowledged G‑d.8 It also meant that in the first nine plagues, those who were afflicted were not killed, so that they could benefit from this revelation of G‑d’s power. But in the tenth plague, since the firstborn were killed, the aim could not have been (as regards the victims) to educate them. It was to punish and destroy them. And in this case the voice of strict justice could claim: What is the difference between the Israelites in their idolatry9 and degeneracy, and the Egyptian firstborn? Surely both deserve punishment? Hence the Israelites’ need to safeguard themselves against the force of destruction—the instrument of strict justice.

These safeguards were of two orders. In Egypt generally, the force of destruction was “given permission” to loose itself. Since it is indiscriminate and has no limitations, no “sign” is a protection against it. Therefore the Israelites had to withdraw to their houses. Within them (since they were “passed over” by G‑d) the plague was subject to a limitation—and so there was room (and necessity) for a “sign” which would single out Jew from Egyptian.

3. Midnight and Essence

But what is still difficult to understand is this: The voice of strict justice raised the question, “What is the difference” between a G‑dless Egypt and a sinful Jewish people? How could a “sign” have answered the claim?

The answer is that the tenth plague was executed by “G‑d Himself in His glory and His essence,” G‑d as He transcends characterization, in particular, as He is beyond the attribute of strict justice. At this level, the accusations brought in the name of severity and justice are silent, inoperative.

This is the connection between the tenth plague and midnight. For midnight is the moment when this all-transcending face of G‑d is revealed. Midnight binds the two halves of the night, the first half which leads from light into darkness and is therefore a symbol of severity and holding-back (gevurah), and the second which leads from darkness into light, and stands for kindness and giving-forth (chesed). And so, momentarily harmonizing these two opposing tendencies and thereby transcending them, midnight is the time at which G‑d in His Essence is revealed.10

Thus at the time of the tenth plague, G‑d displayed his essential love for Israel, a love which in its infinity finds no place for the accusations of the voice of justice. When the voice claims, “Was not Esau Jacob’s brother?” (Are they not equal?) G‑d answers, “Yet I loved Jacob and I hated Esau.”11 For His love for the Jewish people is as deep and invulnerable as the love of a father for his children: “You are the children of the L-rd your G‑d.”12

This is why Moses told Pharaoh the time of the plague (“about midnight”). In this, he was hinting that it would be brought about by G‑d in His transcendence. For otherwise Pharaoh and his court would have been convinced that a plague whose purpose was to destroy and not to educate, would afflict the Israelites as well, since they too were guilty of sins. Only a revelation of G‑d’s unconditional love (i.e., at midnight) would have saved them.

4. Sign and Love

Why, though, did the Israelites still need a sign?

The answer is that to draw down into the physical world a revelation of G‑d, man must perform acts of service, the acts which are specified in the Torah. Even G‑d’s unconditional love, which is always present and constant, requires an active response by the Jew if he is to internalize it and bring it into openness of revelation. But in this case, since the love is unconditional, the response, too, must be unconditional—going beyond the limits of rationality.

Both of the signs—the blood of circumcision and of the Paschal lamb—were of this character. The covenant of circumcision is performed on a Jewish child who is only eight days old, at an age when his faculty of reason is as yet undeveloped. It is a union between the Jew and G‑d which goes beyond the rational. And the sacrifice of the Paschal lamb was at that time so fraught with danger as to constitute an act of self-sacrifice (mesirat nefesh). The lamb was an Egyptian deity. And not only were the Israelites to kill it, but they also had to keep it for four days beforehand with the full knowledge of the Egyptians. Self-sacrifice is never rational. And so the Paschal lamb was itself a sign of a Jewish response to G‑d that surpassed reason.

Therefore these two signs were answered by G‑d with an act of supra-rational love—the love of midnight, of G‑d’s Essence, of the delivery from the tenth plague.

5. Faith and Reason

Now we can resolve an apparent contradiction in the statements of the Rabbis as to the virtue in whose merit the Israelites were redeemed from Egypt. In one place, we find that it was their faith:13 “And the people believed, and when they heard that the L-rd had visited the children of Israel and that He had looked upon their affliction, they bowed their heads and worshipped.”14 In other places,15 it is stated that it was a reward for their signs of blood: “In your blood: Live.”16

But the two opinions are one. The signs were of a bond between Jew and G‑d surpassing reason. And their faith was one which went beyond reason. Before the redemption, “no slave had been able to escape from Egypt because the land was closely shut in (on all sides).”17 How much less reasonable was it to believe that 600,000 could escape, a people broken by the rigors of oppression, and threatened with extinction through Pharaoh’s decree that every male child be drowned. The pure faith with which the Israelites believed in Moses’ mission and G‑d’s promised deliverance went far beyond the rational. And this faith aroused the unconditional love in G‑d for His people, which constituted their inseparable bond. The signs by which it was then expressed, brought the revelation of G‑d’s love down to this world.

6. The Future Redemption

“Like the days of your exodus from the land of Egypt, I will demonstrate wonders.”18 This means the future redemption will parallel the redemption of the past.

The deliverance from Egypt was a reward for the supra-rational faith which was so internalized by the Israelites that it affected even their most extraneous powers (signified by the blood of circumcision) and even the non-human environment (the Paschal lamb).

So, too, will the future redemption be a reward for faith—the faith which disregards the great concealments of G‑d that our exile brings, and which still holds firm to the belief in the Messiah; a faith which does not hover at the outer edges of our minds, but which constitutes our most inward certainty and extends to every facet of our being.

(Source: Likkutei Sichot, Vol. III pp. 864-8, 872)