“has mercy on whom he wants, and he hardens whom he wants.” This phrase has been very misunderstood by many Christians. In order to understand it, there are a couple things we must understand. We must understand the context, particularly Rom. 9:17, and we must understand the Semitic “idiom of permission.”
An idiom is “a phrase or expression whose meaning cannot be understood from the ordinary meanings of the words in it.” (The World Book Dictionary, “idiom”). Idioms often do not make sense when translated literally into other languages, or heard by people who have not been taught what they mean. For example, the American English idiom, “stop on a dime” has nothing to do with a dime, it means “stop quickly.”
It is vital that we understand biblical idioms if we are going to understand the Bible. The “idiom of permission” is an idiom that occurs in the Hebrew language (in fact, in Semitic languages). E. W. Bullinger summarizes it well in his book, Figures Of Speech Used In The Bible, “idioma,” number 4: “active verbs were used...to express not the doing of the thing, but the permission of the thing which the agent is said to do.” The idiom of permission is the reason why many verses in the Bible seem to attribute evil actions to God. Bullinger gives many examples, and a good one comes from Ezekiel 20:25, which says in the KJV: “Wherefore I gave them also statutes that were not good.” Bullinger comments: “God never gave Israel laws that were not good. What the verse is saying in idiomatic language is: ‘I permitted them to follow the wicked statutes of the surrounding nations, mentioned and forbidden in Leviticus 18:3’” (Bullinger, Figures, “idioma”).
It is widely recognized by scholars that in Semitic languages the active verb can be used in a permissive sense. In the Emphasized Bible by Joseph B. Rotherham, the phrase often translated as, “I will harden his [Pharaoh’s] heart” is translated as “I will let his heart wax bold” (cp. Rotherham, Exod. 4:21). In defense of his translation, he offers the following in a footnote: “...the translation in the text above would seem fairer to the average Occidental [Western] mind, and is thoroughly justifiable on two grounds: (1) of the known character of God, and (2) the well-attested latitude of the Semitic tongues, which are accustomed to speak of occasion as cause” (p. 87). Rotherham goes on in an appendix to say “...even positive commands are occasionally to be accepted as meaning no more than permission” and he cites Gesenius’ Hebrew Grammar as more support for his translation.
Marcus Kalisch (May 16, 1828 - August 25, 1885) was a Jewish scholar who was educated at Berlin University where he studied classics, philology, and the Semitic languages, and he also studied at the Rabbinical College of Berlin. He was one of the pioneers of the critical study of the Old Testament in England. At one time he was secretary to the Chief Rabbi. In his commentary on Exodus he says:
“...the phrase ‘I will harden the heart of Pharaoh’ means ‘I know that I shall be the cause of Pharaoh’s obstinacy; my commands and wonders will be an occasion, an inducement to an increasing obduration of his heart.’ And the compassionate leniency of God, who instead of crushing the haughtiness of the refractory king with one powerful blow, first tried to reform him by various less awful punishments, and who generally announced the time of the occurrence of the plagues by the words, ‘Behold, I shall afflict tomorrow,’ in order to grant him time for reflection and repentance; this clemency on the part of God increased Pharaoh’s refractoriness; it was to him a cause of prolonged and renewed resistance.” (quoted in the Appendix of Rotherham’s Emphasized Bible).
To put Kalisch’s explanation into more modern English, we can see why the Hebrew text says “God hardened Pharaoh’s heart” and uses the idiom when God did not in fact harden Pharaoh’s heart. God asked Pharaoh to let the Israelites go. At that point Pharaoh could have said, “Okay,” and let them go, and he and Egypt would have been unhurt. But God’s demand forced Pharaoh to make a choice: He could either let God’s people go, or harden his heart and say, “No,” which we know is what Pharaoh did. As God continued to demand that Pharaoh let the people go, and Pharaoh continued to say “No,” Pharaoh’s heart had to become harder and harder. We know that because the plagues were hurting his kingdom and his people, so he had to become more and more obstinate to not give in to them. Thus, the idiom, “God hardened Pharaoh’s heart,” is a Semitic way of saying that God acted in such a way that Pharaoh had to harden his heart to resist it. God didn’t “harden” Pharaoh’s heart, Pharaoh hardened his own heart because he did not want to obey God’s request.
We use the same kind of idiom in English. If a person does something that upsets us and we say, “You made me mad.” But the person did not actually “make” us mad; anger was our personal response to what the person did to us. Someone else may have the same thing happen to them as happened to us but they not get angry at all. So, when we say, “You made me mad,” we are using an idiom that expresses that anger was our response to what someone else did.
There are dozens of examples of the idiom of permission in the Old Testament. That is not unusual since the Old Testament is large and the idiom of permission was a standard Semitic way of speaking.
To be clear then, we see that the Semitic idiom of permission is when a person reacts to something God has said or done (such as Pharaoh hardening his heart in reaction to God asking him to let Israel go), but the idiomatic way of expressing that reaction is to say that God caused the hardening. Similarly, people do evil as their freewill choice, but because God gave them free will and also made the distinction between good and evil, God is said to create evil. Although God is said to cause the thought or action, in actual fact God does not override the freewill of man, and he neither causes people to sin, nor gives His permission for them to do so.
When the idiom of permission is used, we readers must search for the connection between God and the action or reaction (often a sin someone is committing), and sometimes that connection is very subtle. It has been said that one cannot “break” God’s laws, but only breaks himself against them, because they are “immovable objects.” God has set up the universe to function according to many laws and principles, which He said were “very good” (Gen. 1:31). God’s laws cannot be broken, and that is true in both the physical and spiritual world. A farmer who disregards God’s principles of sowing and reaping will not prosper, and via the biblical idiom of permission we might read that “God ruined him.” Similarly, a rock climber who disregards the worn-out state of his safety rope may fall to his death because of God’s law of gravity if his rope breaks, and in the Semitic idiom it might be said that, “God killed that careless person.” Is God to blame because He set these laws in place? Of course not. Did God really kill the careless rock climber? No. But in the Semitic idiom, it might be expressed that way. [For more on the idiom of permission, see commentary on Exod. 4:21, and see Graeser, Lynn, Schoenheit, Don’t Blame God, Chapter 5, “God Is Good (with Figures)”].