Augustine of Hippo
God clearly states, “I will harden Pharaoh's heart” in a way that suggests He is providing an explanation for His actions. He declares, “I will harden Pharaoh's heart and demonstrate numerous signs and wonders in the land of Egypt,” implying that the hardening of Pharaoh's heart is essential for the increase and manifestation of God's signs in Egypt. Thus, God skillfully utilizes the hearts of the wicked to reveal His intentions to the righteous, or to those whom He is about to redeem.
Read more (259 words)
Although every heart is prone to deception—meaning that any heart inclined toward evil does so out of its own vice, arising from misguided desires—these desires often shift and morph. When these desires lead to poor choices, the soul finds itself driven by these impulses. Whether these impulses exist independently or not, they are beyond the control of man and stem from the hidden, perfectly just, and wise foreknowledge of God, who orchestrates and governs the world He has brought into being. Therefore, Pharaoh possessed a heart that was unresponsive to mercy despite God's patience; instead, it leaned toward evil, which was itself a manifestation of his vice.
The outcome of a heart so steeped in wickedness that it opposed God’s commands is what is termed as hardened; it did not respond willingly but remained obstinate. This occurred by divine design, preparing such a heart not as unrighteous but as a clear form of just punishment, whereby those who fear God are corrected. For instance, if one is presented with a monetary incentive for committing a crime, one person may be tempted by greed, while another may scorn financial gain. One consents to commit the crime, while the other does not. However, the mere existence of the temptation does not rely on either individual. Similarly, evil individuals encounter influences that lie outside their control, yet they reveal the consequences of their own vices borne from their desires. Thus, we must reflect on whether the phrase, “I will harden,” might also convey the meaning, “I will demonstrate how hardened I am.”