It is stated in the Parashat Va'era (Exodus 7:19): "And the Lord said to Moses, 'Say to Aaron: Take your staff and stretch out your hand over the waters of Egypt... and they shall turn to blood, and there shall be blood throughout all the land of Egypt, both in the wood and in the stone.'" And Rashi comments: "Say to Aaron – since the Nile protected Moses when he was cast into it, therefore it was not struck by him neither in the plague of blood nor in the plague of frogs, but it was struck by Aaron."

Here, although Rashi does not explicitly mention the terms 'gratitude' and 'ingratitude,' it is simple and clear that this was his intention, and the intention of the Sages, whose words (Shemot Rabbah 9:10) Rashi draws from.

It seems that aside from the basic and simple obligation of recognizing the good, which applies to every person at all times, here, in the performance of signs and wonders that were a central component in the unfolding process of redemption, the emphasis on recognizing the good, as opposed to ingratitude, was necessary and important many times over. This is because the matter of recognizing the good was deeply rooted and connected to the very essence of the redemption of Egypt and the processes involved in it. This is because a significant part of the 'shell of Egypt' and its impurity was the evil of ingratitude, as will be shown, so consequently, the redemption from there was dependent and connected to the opposite of this flaw – recognizing the good.

Where is the evil of ingratitude manifested in the impurity of Egyptian culture? The answer to this can be found if we look at the figure of Pharaoh – here we have Pharaoh, the mighty and powerful king, whose kingdom was known to be the center of the world at that time, and whose government's authority extended over all the surrounding nations. This Pharaoh himself, or at least one of the kings preceding him, was potentially about to fall in the not-too-distant past into an unprecedented crisis, a crisis of seven years of severe famine, so severe that it could have wiped out the population of Egypt and the surrounding lands. And who saved him at that time? The Holy One, Blessed be He, who revealed the future to him before it came in the dreams of the cows and ears of grain, and brought Joseph the Righteous to interpret them, and even advised him appropriately. As a result, not only was he and his land saved from a terrible crisis of destruction, but he was also strengthened in his kingdom as had not been seen in the kings before him. Joseph collected all the money found in the land of Egypt and the land of Canaan, all the horses, flocks of sheep, cattle, and donkeys, and as if that were not enough, he even acquired all the lands of the country from its people and made them his eternal servants to pay him a fifth of the produce as a perpetual law, as told at the end of Parashat Vayigash (Genesis 47:14–26).

And after all these things, after the Lord saved him and his kingdom and even elevated him above all the kings before him, what was this vile man's response to the word of the Lord brought by Moses and Aaron: "Thus says the Lord, the God of Israel: Let my people go, so that they may celebrate a festival to me in the wilderness"? – Absolute denial: "Who is the Lord, that I should obey his voice to let Israel go? I do not know the Lord, nor will I let Israel go"...

Is there any more brazen and severe ingratitude than this? It is astonishing! This is Pharaoh, and this is the corrupt Egyptian culture.