Pharaoh’s heart hardening is a recurring theme in the Exodus account.
“The hardening of Pharaoh’s heart is referred to no less than twenty times in the course of the story of the Exodus.”
Exod 8:32 (KJV)
32 And Pharaoh hardened his heart at this time also, neither would he let the people go.
In this passage, harden in Hebrew is kabad (כָּבַד). This word has a minimum of 3 meanings and most likely all three were implied by Moses here.
One is harden, as in a stubborn heart and not pliable to change. Another meaning is glorify/honor as in Pharaoh glorified his own wishes. A third meaning is make heavy. So, another way to translate this passage is “and Pharaoh made his heart heavy at this time also”.
In the Book of the Dead, the Egyptians believed their hearts were weighed in the afterlife and it had to be light in order to pass judgment.
The Weighing of the Heart from the Book of the Dead of Ani. At left, Ani and his wife Tutu enter the assemblage of gods. At center, Anubis weighs Ani’s heart against the feather of Maat, observed by the goddesses Renenutet and Meshkenet, the god Shay, and Ani’s own ba. At right, the monster Ammut, who will devour Ani’s soul if he is unworthy, awaits the verdict, while the god Thoth prepares to record it. At top are gods acting as judges: Hu and Sia, Hathor, Horus, Isis and Nephthys, Nut, Geb, Tefnut, Shu, Atum, and Ra-Horakhty.
After confirming that they were sinless, the deceased was presented with the balance that was used to weigh their heart against the feather of Maat. Anubis was the god often seen administering this test. If the deceased’s heart balanced with the feather of Maat, Thoth would record the result and they would be presented to Osiris, who admitted them into the Sekhet-Aaru. However, if their heart was heavier than the feather, it was to be devoured by the Goddess Ammit, permanently destroying the soul of the deceased
The heart was considered the most important body part according to the Ancient Egyptians. They felt that the heart was the most important because it was the only part of the body that knew what a person was feeling and thinking and the good or bad deeds that they had done.
The heart was so important that Ancient Egyptians would not remove the heart when someone died, and it was the only organ that would stay in the body. When a person became a mummy, they still had their heart in their body.
The heart was the seat of a person’s personality and spirit, and so the most important part of the body. It was not removed during mummification, but was protected by a powerful amulet – the heart scarab.
When a person entered the Hall of Judgment after death, it was their heart that was weighed against the feather of Ma’at to determine whether they had lived a good life and deserved to join the blessed dead. Part of this ritual was the Negative Confession (recorded in the Book of the Dead) , in which the deceased listed the crimes that they had not committed. If they failed this test, their heart was thrown into the lake of fire or gobbled up by the fearsome Ammit and they suffered the feared second death.
The heart was weighed against the Maat. Maat was the cosmic order of truth and justice and it was the responsibility of the Pharaoh to establish Maat.
The feather represented Ma’at, the central Egyptian value that included the concepts of truth, balance, order, harmony, justice, morality, and law. Not only was this fundamental to Egyptian culture. It was the task of the Pharaoh to ensure that it prevailed. This had been an Egyptian principle since a thousand years before the Exodus, found in Pyramid texts dating from the third millennium BCE. Ma’at meant cosmic order. Its absence invited chaos. A Pharaoh whose heart had become heavier than the Ma’at feather was not only endangering his own afterlife, but threatening the entire people over whom he ruled with turmoil and disarray.
During the series of plagues, Pharaoh continually hardened his heart (made his heart heavier) and so it was a reference to his ultimate judgment when his heart would be weighed in the afterlife.