“….And all the water that was in the Nile turned to blood…” – Shemot 7:20

וַיֵּהָפְכוּ כָּל הַמַּיִם אֲשֶׁר בַּיְאֹר לְדָם – שמות ז, כ 

The Jewish people were so oppressed in Egypt that even Moshe struggled to understand how this could be part of G-d’s plan. Their misery was so profound that they refused to accept Moshe’s message from G-d that their redemption was imminent. Only when G-d struck the Egyptians with the Ten Plagues, starting with the water in Egypt turning to blood, did the grip of Egypt bondage began to crumble.

“In every generation and every day, one must regard himself as though he has come out of Egypt on that very day” (Mishna, Pesachim 10:5, cf. Tanya Chapter 47). As explained in Chassidus, this means that we must constantly strive to escape our personal Egypts, the inner limitations that compromise and restrict our devoted service of G-d. Accordingly, the Ten Plagues represent ten steps through which even the most formidable internal barriers can be breached, to allow our G-dly souls to freely and fully express their attachment to G-d.

In the first Plague, the waters of the Nile River turned to blood. Water is naturally cold; the waters of the Nile, the Egyptian deity, thus represent coldness and impassiveness toward whatever is associated with the One and Only true G-d. All other spiritual ills start from this cold attitude, and therefore the very first step toward escaping spiritual bondage is to rid your self of the cold waters of the Nile. Replace them with warm and life-carrying blood instead – passionate warmth and lively enthusiasm in all things G-dly.

One does not remain forever dispassionate about both good and evil. Even if he observes all the mitzvos, but does so coldly and apathetically, such detachment invariably leads to being attracted to things that challenge and counter a life of holiness. Coolness is therefore the number one tool that the Yetzer Hara, the evil inclination, threatens us with. Infusing our Judaism and Torah observance with passion and excitement is therefore the first and most crucial step toward the escape from Egypt.

—Likkutei Sichos vol. 1, pp. 119-124