HARDENED HEARTS

In our text today, it mentions four times that the Lord hardened Pharaoh's heart (Ex. 10:1,20,27; 11:10) during the plagues so that people would see His power. In earlier chapters leading up to this, Pharaoh and his servants hardened their hearts (Ex. 8:15,32; 9:34). So it seems they already had hard hearts before the Lord stepped in a few times near the end. Again God hardened Pharaoh's heart to chase the Israelites (Ex. 14:4,8,17).

John 12:40 references Isaiah's words, “He [the Lord] blinded their eyes and hardened their heart, so that they would not see with their eyes and understand with their heart...” In Rom. 9:18,  we see that “God has mercy on whom He chooses to have mercy, and He hardens whom He chooses to harden”.

Even the disciples struggled with hardened hearts in comprehending Jesus' miracles (Mark 6:52; 8:17). While God hardens some hearts, we are clearly instructed to make sure that our hearts are not hardened. “Do not harden your hearts as in the rebellion, in the day of testing in the wilderness.” (Heb. 3:8 ). But exhort one another each day, as long as it is called ‘Today,’ that none of you may become hardened by sin’s deception.” (Heb. 3:13). I am encouraged by today's text to remain totally committed to the Lord, spending time in His Word daily, talking with Him in prayer, and following the leading of the Holy Spirit, so that my heart will remain open to His leading.
Quotes from NET 2nd ed.