Comentario sobre Exodo 10:20

ויחזק ה' את לב פרעה, “G’d reinforced Pharaoh’s resolution.” It is totally unnatural for a person experiencing the kind of plagues Pharaoh and the Egyptians endured not to suffer a total mental collapse. The Torah had already described how, during the first five plagues, Pharaoh had drawn on his psychological reservoirs of obstinacy to stand fast in face of these plagues. Starting with the sixth plague, pestilence, however, G’d had lent him psychological support as we read for the first time in 9,6. This bears out what the prophet said in Jeremiah 18,6, “O House of Israel, can I not deal with you like this potter?- says the Lord. Just like clay in the hands of the potter so are you in My hands!” The prophet continues: “one moment I may decree that a nation or a kingdom shall be uprooted, etc., but if that nation turns back from wickedness I change My mind, etc.” Similarly, Solomon states (Proverbs 21,1) "Like channeled water is the mind of the king in the G-d’s hand; He directs it to whatever He wishes".