In Exodus 4:21 and 7:3 God told Moses that he was going to harden the heart of Pharaoh so that he would refuse to let the Israelites leave Egypt. In that way God would show his power and get glory. The phrase "harden the heart" is actually three different phrases in Hebrew, but all three refer to being stubborn. The most common is "strengthen the heart" which does not sound in English as harsh as harden the heart. Another phrase is "make heavy the heart"; it would not do to literally translate this into English because a heavy heart refers to being sad, not stubborn. The third phrase "harden the heart" is the one that is used in the New Testament and has become the standard way to translate all three Hebrew phrases. So Pharaoh was stubborn. But even though God told Moses that he would harden Pharaoh's heart, the Exodus story makes it clear that Pharaoh hardened his own heart before God hardened it even more. Sometimes the text just says that Pharaoh's heart was hardened and does not say who hardened it. But Exodus 8:15 and 8:32 make it clear that Pharaoh hardened (made heavy) his own heart. It is not until Exodus 9:12 that the LORD hardened (strengthened) the heart of Pharaoh. Then again in Exodus 9:34 Pharaoh hardened (made heavy) his heart with his servants agreeing. Then in Exodus 10:20, 27; 11:10 the LORD hardened (strengthened) Pharaoh's heart. There is a lesson in this account for us. If we continue to stubbornly refuse to obey God, he will get glory from us by strengthening our resolve to disobey. We, just as Pharaoh, will become an example of the evil of the stubborn heart. Let us resolve to have a heart always open to his will.
http://www.bterry.com/tidbids/hardheart.htm Last updated on September 1, 2025