Blood (דם)
Frogs (צפרדע)
Lice (כנים)
Beasts (ערוב)
Pestilence (דבר)
Boils (שכין)
Hail (ברד)
Locusts (ארבה)
Darkness חשך
Death of the First Born (מכת בכורות)
WHY DID GOD HARDEN PHAROAH'S HEART?
Which of thse potential answers resonates with you the most? Which resonates with you the least? Do you have an alternative answer that doesn't appear here?
לפיכך כתוב בתורה ואני אחזק את לב פרעה לפי שחטא מעצמו תחלה והרע לישראל הגרים בארצו שנאמר הבה נתחכמה לו נתן הדין למנוע התשובה ממנו עד שנפרע ממנו לפיכך חזק הקדוש ברוך הוא את לבו ולמה היה שולח לו ביד משה ואומר שלח ועשה תשובה וכבר אמר לו הקב"ה אין אתה משלח שנאמר ואתה ועבדיך ידעתי וגו' ואולם בעבור זאת העמדתיך כדי להודיע לבאי העולם שבזמן שמונע הקדוש ברוך הוא התשובה לחוטא אינו יכול לשוב אלא ימות ברשעו שעשה בתחילה ברצונו
Therefore it is written in the Torah: I will harden Pharaoh’s heart (Ex. 14:4) – since he initially sinned of his own initiative and abused Israel, who were living in his land, as it says, Come, let us deal cleverly with them (Ex. 1:10), judgment was rendered to deny Pharoah's judgement until [God] punished him – therefore the Holy Blessed One hardened [Pharaoh’s] heart. So why did [God] send Moses with the message: “Release [the Israelites], and repent,” ... In order to inform humanity that when the Holy Blessed One denies repentance to a sinner, the sinner can not repent – rather the sinner will die in the wickedness that the sinner initially committed intentionally.
The Lord hardened his heart, so that he imagined that the plague was accidental rather than providential (from God)...only then could it be demonstrated whether his repentance was freely motivated.
-Albo, Sefer Ha-ikkarim (Book of Principles)
Why were the waters first transformed into blood? Because Pharoah and the Egyptians worshipped the Nile. Said the Holy One Blessed be He: I shall strike first his God, and then his nation! As the saying goes, Strike the God, and the priests will tremble!
Midrash, Shemot (Exodus) Rabbah, 9,8
Why did he bring upon them the plague of blood? Because they threw the children of the Israelites into the river; as it is written, "Every male child that is born, shall ye cast into the river (Exodus 1:12). Therefore, he punished them through the waters of the nile.
Midrash, Mishnat Rabbi Eliezer 19
I've been thinking of that confusing verse in Exodus when God tells Moses that he will harden Pharaoh's heart (Exodus 7:3) – and it's an action God repeats throughout the story. Wasn't Pharaoh's heart hard enough already? A dictator who saw himself as God believing no one was above him, who oppressed an entire race out of fear and for his own gain. A man who even when he saw his own people suffer, refused to yield. Would anything stop him?
Does God Love Destruction?
וא"ר יוחנן מפני מה לא נאמר כי טוב בהודאה זו לפי שאין הקב"ה שמח במפלתן של רשעים ואמר רבי יוחנן מאי דכתיב (שמות יד, כ) ולא קרב זה אל זה כל הלילה בקשו מלאכי השרת לומר שירה אמר הקב"ה מעשה ידי טובעין בים ואתם אומרים שירה
This is because the Holy One, Blessed Be He, does not rejoice at the downfall of the wicked. And Rabbi Yohanan said: Why has it been written (Exodus 14:20): "This one did not draw near to that one the whole night."? The ministering angels sought to recite a song, [but] the Holy One, Blessed Be He said: The work of My hands is drowning in the sea, and you are reciting a song???