שמות פרק ו, ו וְהוֹצֵאתִי וְהִצַלְתִי וְגָאַלְתִי וְלָקַחְתִי
The Rabbis established the four cups of wine at the Seder based on the four words of Geulah in the verse. They specifically established this custom with cups of wine, and not with other liquids such as milk or honey or oil. The drinking of wine brings out the remembrance of a person’s deep love, which is normally not in one’s consciousness.
Paroh's Challenge and the Plagues
שמות פרק ז, ט כִי יְדַבֵר אֲלֵכֶׁם פַרְ עֹה לֵאמֹר תְנוּ לָכֶׁם מוֹפֵת
The use of the word לכם is not understood. How is the sign to you? One might understand from the concept the לכם – משלכם, which implies ownership (like by the Lulav and Estrog). Thus, Paroh is telling Moshe and Aharon that they should prove themselves with a miracle of their own, particular and unique, that could not be duplicated by Paroh’s own magicians. And in the end, that is what happened when Arahon’s staff swallowed all the magicians’ snakes.
שמות פרק ז, יד כָבֵד לֵב פַ רְ עֹה
The use of the word כבד (which also means liver) is meant to imply the concept of difficult and hard. The cooking of this bodily organ is different from cooking all the other organs of the body. All the other bodily parts become increasingly tender as one cooks them. The liver becomes harder as one cooks it. This is the allusion to the continuing hardening of Paroh’s heart that occurs.
שמות פרק ח, יב נְטֵה אֶׁת-מַטְךָ וְהַךְ אֶׁת -עֲפַר הָאָרֶׁץ וְהָיָה לְכִנִם בְכָל-אֶׁרֶׁץ מִצְרָיִם
To understand why the order of the plagues, and why the lice infestation follows the plagues of blood and frogs, one needs to remember the Talmudic story (גיטין נ"ו ב') regarding the Roman army leader Titus, the Evil one, who destroyed the Holy Temple. On the way back to Rome, the ship was assaulted by high water. Titus challenged G-d that His power was only on the seas. Thus, G-d waited until the ship reached land and send one of His tiniest creatures, the gnat, into the brain of Titus. The gnat resided in Titus brains for 7 years, causing great pain.
The same lesson was presented to the Egyptians. After the first two plagues involved the water, G-d now sent another of His tiny creatures to cause great pain and discomfort. This plague teaches that G-d’s authority exists over the entire earth and all creatures within the earth’s domains.
שמות פרק ח, יז כִי אִם-אֵינְךָ מְשַלֵחַ אֶׁת -עַמִי הִנְנִי מַשְלִיחַ בְךָ וּבַעֲבָדֶׁיךָ וּבְעַמְךָ וּבְבָתֶׁיךָ אֶׁת -הֶׁעָרֹב וּמָלְאוּ בָתֵי מִצְרָיִם אֶׁת- הֶׁעָרֹב וְגַם הָאֲדָמָה אֲשֶׁר -הֵם עָלֶׁיהָ:
וגם האדמה “and also the land” – what does this come to add? One explanation is that this plague also included an animal that is attached to the earth (Talmud says such an animal existed). Another explanation is the wild animals also went into the houses and the houses became very crowded, forcing many people outside. Thus, in addition to the crowding in the houses due to the plague, the land outside the houses became full.
ביד חזקה זו הדבר כמה שנאמר הנה יד ה' הויה במקנך
This verse is not clear why the Hand of HaShem specifically refers to the plague of דבר (the fifth plague of death of the cattle through a unique disease). It is possible to explain that each plague represented a finger. Thus, upon reaching the fifth plague, a complete hand was fulfilled.
Why was this specific plague selected to present this concept of a complete hand? It is possible to attribute to the story that after Dovid erred in counting the Jews (that it is not permitted to count the Jews per Yuma 22b) the prophet Gad stated in the name of HaShem that Dovid could select a punishment from three choices: Dever in the Eretz Yisrael for three days, or seven years of famine, or for three months the enemies would oppress the Jewish nation.
And Dovid answered (Shmuel 2, chapter 24,14) נפלה נא ביד ה' (Let us fall now by the Hand of HaShem). And it is explained in the Aggada that by using these words, Dovid indicated a selection of Dever. Dovid reasoned that if he had selected famine, others could say Dovid is protected against hunger due to his wealth but not the common people. And if Dovid selected fleeing from oppressors, others could say he would be protected by the strong personal guards, but not so the common people. Thus, Dovid selected disease which affected everyone equally.
Therefore, all agree that it is impossible to be saved from this unique disease. Thus, everyone was clear that this type of plague is the Hand of HaShem that applies to all and salvation is only available from HaShem (like Dovid indicated in his selection).
