but he who hardens his heart will fall into evil (Mishlei 28:14).
Pharoa decided not to send the Jews out of Egypt.
He hardened his heart.
Question: Pharoa's self destruction was unprecedented. He was shooting himself in the foot. He destroyed his empire. He could have let them go and salvaged the remainder of his Kingdom.
Rabbeinu Bechaye points out the reason why Pharoa did not send them out is because he was cruel. The midah of achzorius cruelty that he possessed was so much a part of him that he could not overcome it.
It seems that this trait is what led about to his personal downfall.
Pharoa hardened his own heart the first five times he was smitten by plagues. This led to him being cruel to his own self. Cruel to his own people. Cruel to his own country.
Mitzvos and Midos Tovos have the opposite effect on people.
They change who we are. They change our essence.
They make our decisions in life different decisions.
Purer Decisions. Holier Decisions.
Midos Tovos leads to Avodas Hashem.
"Im lo litakein es haMidos lamah li chaim"
רמב"ן דברים פרק ו
ועשית הישר והטוב בעיני ה' - על דרך הפשט יאמר תשמרו מצות השם ועדותיו וחקותיו ותכוין בעשייתן לעשות הטוב והישר בעיניו בלבד. ולמען ייטב לך - הבטחה, יאמר כי בעשותך הטוב בעיניו ייטב לך, כי השם מטיב לטובים ולישרים בלבותם...