Foreknowledge is an interesting twist, doctrinally speaking. It changes things to know God does not have to wait to see what we do and then react to it. Instead He knows what is going to happen before it does. Therefore He doesn’t consider anything as it happens but whatever decisions He makes, were made in advance.
Some assume that since God knew what would happen in advance, He must also have made all the decisions. I don’t believe this logically follows. All of us who have been parents have known at times what our children were going to do before they did it. Perhaps by the look on their face, an established pattern, or perhaps a lack of experience, but however we knew, we knew. Many of those times we decided how we would respond before the child took the action. Why can’t we believe that God does the same thing, except much, much better?
Others understand that God can choose His reaction to our choices in advance without making every decision for us, but believe that we are incapable of making the most important decisions. Specifically, they believe that no man can choose Christ, and instead Christ chooses us. But I think that to believe this you have to ignore the importance of the concept of foreknowledge at the times the word is used in Scripture.
If I recall correctly the word appears four times in the New Testament. Acts 2:23 talking about God’s plan to redeem us in Christ. Romans 8:29 where he is describing the predestined. Romans 11:2 referring to His relationship with Israel. And finally in 1 Peter 1:2 while describing the chosen.
Three of four uses of the word then are directly related to God making choices and how His foreknowledge played into the decision. If God determined who would be saved then it would make sense that the Bible would describe His decision making prior to His foreknowledge or perhaps leave foreknowledge out of the picture completely. But if His foreknowledge is described preceding His decision making, then it would seem that what He is saying is He was responding in some manner to our decision, specifically our decision to receive His offer of salvation.
As I said three of four uses of the word combine foreknowledge and God’s choices. Two of these have His foreknowledge mentioned as the basis for His decisions and actions. Romans 8:29 does this by setting up a series that moves from foreknowledge to predestination to calling to justification to glorification. In 1 Peter 1:2 He describes his choice as being according to His foreknowledge. So both of these verses strike me as saying God was responding to something about us. He chose how He would respond before the event actually happened, but foreknowledge allows this possibility.
The other verse that combines foreknowledge and God’s choice of actions puts His choice first, mentioning it prior to His foreknowledge. This is Acts 2:23, where He is describing his decision to have Jesus die for us on the cross. In this case it makes sense to mention the decision first because He is referring to His own decision making rather than His advance knowledge of someone else’s decision. He chose to redeem us and then held to His knowledge of His own plan.
I’d be happy to hear your ideas on my analysis, as long as they are civil. But it appears to me that understanding election, God’s choice, or predestination requires that we also evaluate foreknowledge.
One of the most fascinating interpretations of predestination I have seen:
Pastor and author Tim Warner describes:
“Paul was not referring to some prior knowledge in the mind of God before creation. Nor was He speaking about predetermining their fate. He was referring to those whom God knew personally and intimately, men like Abraham and David. The term “foreknew” does not mean to have knowledge of someone before they were conceived. The verb “proegnw” is the word for “know” (in an intimate sense) with the preposition “pro” (before) prefixed to it. It refers to having an intimate relationship with someone in the past…Literally, we could render Rom. 8:29 as follows: “For those God formerly knew intimately, He previously determined them to be conformed to the image of His Son.” The individual saints of old, with whom God had a personal relationship, were predestined by Him to be conformed to the image of Christ. That is, God predetermined to bring their salvation to completion by the sacrifice of Christ on their behalf.” 
Thanks for commenting. I am assuming two things. One you mean Tim Warner’s description is fascinating rather than my description is fascinating, and two that you agree with him and are presenting his statements as different than my own. If I am wrong on either of those two assumptions my discussion may not be relevant.
I agree, of course, that the passage is not saying God decided in advance who would be saved and lost.
I disagree though with the practice of taking the Old Testament concept of know, which is intimate knowledge hence, Adam knew Eve and she conceived. But the word in the New Testament does not carry this intimate inference. But he is in good company, a lot of writers and theologians have done the same thing. The pro prefix is either intensive or temporal, but not both. So its either modifying the word ginosko to intensify it to mean intimate knowledge or it is modifying it on a timeline referring to something previously known. The context fits for previously known.
The main difficulty of his perspective is that he takes these two verses to be referring to OT characters when the entire previous context was about NT believers and by application, us. I would suspect Paul broke into the use of 3rd person plural, those, instead of 1st person plural, us, because he wanted to speak of a realities for all believers not just those of his age.
The verb is proginosko, when transliterated. Its easy to get w’s mixed in when you are writing in English and thinking about Greek because the omegas sneak in there.
Of course, the final statement is correct. God decided in advance that His plan of salvation would be completed in Jesus.
Well, I’m not a Greek scholar, but it does seem odd that Paul places that whole sequence in past tense: 29 For those whom he jforeknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers. 30 And those whom he predestined he also called, and those whom he called he also njustified, and those whom he justified he also glorified.”
Why not say: Those he foreknows, he also justifies and those he justifie, he also glorifies?
I suppose its a fair question. Although if it was as you suggest I would expect Foreknew to remain in past tense, after all if its not known from previous times forward then by definition its knowledge and not foreknowledge. Similarly for predestination as God making the plan in advance is the point. So perhaps Justified could have been in present tense and glorified could have been in future tense.
I just looked it up and I believe what I am seeing is that the verbs are in 1st Aorist, Active, Indicative, Third Person, Singular. If you are familiar with Greek aorist it is a past tense, but syntactically often is used in other forms. In this case, I would syntax it as gnomic aorist, meaning that the author is discussing timeless truths.
But take this with a grain of salt, because I don’t recognize the exact form. It had the epsilon prefixed to the verb that is the trademark for aorist, so to speak. The suffix then is sigma epsilon nu, which I don’t recognize. So I just spent a bunch of time with a standard verb chart and it is not listed anywhere in that exact form. So it might be something else but I still believe aorist because of the prefix.
Whatever the form is, it is used for predestined, called, justified and glorified. The verb for foreknew is in a slightly different form because of the nature of the stem, but I believe it to be aorist as well, having the tell tale Epsilon prefix between the basic word and the prefix pros. The way that works is the prefix pi rho omicron sigma is shortened to pi rho omicron. Then when the epsilon is added in between the prefixes omicron is lengthened to an omega. So then it looks like pi rho omega as the prefix.
Well, maybe that is more than you need to know. The short answer is Paul used aorist, which technically is a past tense but was used for any situation which got out of the ordinary way of thinking about time.