God is omniscient.

That is, God knows everything that could be, would be, has been, is, and will be.

But how does God know the future? Upon what does His knowledge depend?

Some people (e.g., Calvinists) claim that God’s foreknowledge depends upon His foreordination. For example, Lewis Sperry Chafer said, “Nothing could be foreknown as certain that had not been made certain by foreordination, nor could anything be foreordained that was not foreknown.” That is, God only knows the future because He has decreed everything that will happen in the future. Otherwise, God could not know it.

Is that claim true?

I think it faces two important objections.

First, there is the problem of evil. If God foreordains everything that happens, and sin and evil happen, then God foreordains sin and evil. That would make God worse than the devil, since the devil would only be carrying out what God Himself foreordained. On this view, God is the source of all evil and suffering.

Second, there is direct Biblical evidence that God knows things that He has not foreordained. For example, in an often-quoted passage on the subject of God’s omniscience, David asked the Lord what would happen if he stayed in the city of Keilah (which indicates that David assumed God knew the future). Would the men of Keilah give him over to Saul?

“O Lord God of Israel, Your servant has certainly heard that Saul seeks to come to Keilah to destroy the city for my sake. Will the men of Keilah deliver me into his hand? Will Saul come down, as Your servant has heard? O Lord God of Israel, I pray, tell Your servant.”
And the Lord said, “He will come down.”
Then David said, “Will the men of Keilah deliver me and my men into the hand of Saul?”
And the Lord said, “They will deliver you.”
So David and his men, about six hundred, arose and departed from Keilah and went wherever they could go. Then it was told Saul that David had escaped from Keilah; so he halted the expedition (1 Sam 23:10-13).

God’s answer to David shows that the Lord knew what the men of Keilah would do, i.e., God knew that if David stayed, they would deliver him over to Saul. That is an example of God’s “middle knowledge.” So what did David do after being given that information? Sensibly, he left! He didn’t want to be delivered over to Saul. And because he left Keilah, he avoided that result. And God, in His omniscience, no doubt also knew what David would choose to do.

Here’s the point: God knew something that didn’t actually happen. That means God knew something that He did not foreordain. In his book, The Unseen Realm, Michael Heiser draws this same conclusion:

Why is this significant? This passage clearly establishes that divine foreknowledge does not necessitate divine predestination. God foreknew what Saul would do and what the people of Keilah would do given a set of circumstances. In other words, God foreknew a possibility—but this foreknowledge did not mandate that the possibility was actually predestined to happen. The events never happened, so by definition they could not have been predestined. And yet the omniscient God did indeed foresee them. Predestination and foreknowledge are separable (The Unseen Realm, pp. 64-65, emphasis his).

Therefore, Calvinists like Chafer are wrong—God’s foreknowledge does not always depend upon His foreordination (though sometimes it may!). Instead, God has what is called simple foreknowledge of the future. That is, God knows what you would choose, and what you will choose, without predestining your choices.