by Rabbi Aaron Samuel Tamares, a Lithanian Orthodox rabbi (1869-1931),
from The Family Participation Haggadah by Noam Zion and David Dishon.

For I will go through the land of Egypt in that night (Exodus 12:12). The Rabbis interpret this verse: I, and not an intermediary. Now obviously the Holy One, blessed be He, could have given the children of Israel the power to avenge themselves upon the Egyptians, but He did not want to sanction the use of their fists for self-defense even at that time. At that moment they might merely have defended themselves against evil-doers, but in the end defenders become aggressors.

It came to pass at midnight (Exodus 12:29). The Holy One, blessed be He, took great pains to remove Israel completely from any participation in the vengeance upon the evil-doers, to such an extent that they were not permitted even to see the events. For that reason, midnight, the darkest hour, was designated as the time for the deeds of vengeance, and the children of Israel were warned not to step outside their houses at that hour.

None of you shall go out of the door of their house untill the morning...that there not be in your midst the plague of the destroyer. (Exodus 12:22-23). The language itself is very precise. Your abstention from any participation in the vengeance upon Egypt will prevent the plague of vengeance from stirring the power of the destroyer which is in you yourself.

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There is a custom at the Seder (the festive meal of Passover) that when we mention the ten plagues inflicted on Egypt, we remove a drop of wine from our cup for each of the plagues. Here are some related commentaries:

By spilling a drop of wine, from the Passover cup for each plague, we acknowledge that our own joy is lessened and incomplete. For our redemption had to come by means of the punishment of other human beings. Even though these are just punishments for evil acts, it says, If your enemy falls, do not celebrate, if he trips, let not your heart rejoice (Proverbs 24:17). - Don Isaac Abrabanel, refugee from the Expulsion from Spain.

God is not happy at the downfall of the wicked...When the angels tried to sing songs of praise to God at the Red Sea [where the Egyptian hosts were all drowned while pursuing the Israelites], God silenced them: "My handiwork, my human creatures are drowning in the sea and you want to sing a song of praise?" (Talmud, Megillah 10b)