"And God said to Moses: 'Go in unto Pharaoh; for I have hardened his heart, and the heart of his servants, that I might show these My signs in the midst of them'" Exodus 10:1
A five-year-old in the community came to see me to complain that God cannot be very nice if He killed Pharaoh's son. The theology behind the hardening of Pharaoh's heart has challenged Jews of every age and throughout the generations.
Resh Lakish, a talmudic sage, is quoted as saying, "When God warns someone once, twice and even a third time and that person does not repent, then and only then does God close the person's heart against repentance and exact punishment for his sins."
However, we have developed two distinct images of God; on the one hand, we have the God of our Torah, who hardens Pharaoh's heart, punishes Adam and Eve along with every future generation and prevents Moses from seeing his task through by entering the Promised Land.
Yet on the other hand, we have the God of our liturgy who is loving and compassionate, responds to our prayers and forgives. The nuanced difference of these two images is highlighted when we sing of God's Thirteen Attributes. The words of the Torah are edited in such a way that we turn the God of Torah who "forgives sin, wrong-doing and failure but does not leave the guilty unpunished, visiting the sin of the parents on children and children's children" into the God of our liturgy who simply "forgives sin, wrong doing and failure".
We should be uncomfortable bringing the God of the Ten Plagues into our lives, yet we should not be afraid to do what the liturgists have done and try to tease out of the Torah what informs our lives for the better.