There is a Talmudic interpretation of the Passover story which says that when the Egyptians had been drowned in the Red Sea, after the Lord had led the Israelites through safely, the angels and hosts of Heaven were celebrating. The Lord, blessed be He, grew upset with them. He commanded that they stop celebrating, saying, “Those were my children, too.”

The Israelites may have been His chosen people, but the Egyptians were His children too. And so the Lord, being merciful and loving, mourned having to act against them so severely. This can be seen throughout the entire story of the Lord's servants confronting Pharaoh. Pharaoh and the Egyptians were given so many chances. The Lord wanted His chosen people Israel to be set free, and would ultimately do whatever was needed to get to that goal, but did not want to act too severely against the Egyptians. He started off with lesser plagues. As Pharaoh continued to be stubborn, the Lord gradually increased the severity of the plagues, until the point that He slayed the firstborns of the Egyptians. At this point, finally, Pharaoh allowed the People of Israel to go... but then he changed his mind, and sent his troops after them anyway. And so the Lord our God, leading our people out of slavery, was forced to kill our enemy in the Red Sea.

Many interpret the spilling of a little wine for each plague to be the showing of compassion for the Egyptians. The Egyptians were the Lord’s children as well, even if they were not His Chosen People. And the general public suffered for the stubbornness of Pharaoh, just as the Israelites suffered in slavery of Pharaoh. It is for that reason that the Lord wept for the Egyptians, and that we should do so as well; even as we remember in joy that we once were slaves but now are free, we must also remember that freedom came at a terrible price.

haggadah Section: -- Ten Plagues