What does Romans 8:29 mean?
We Christians did not stumble into this relationship with God. Paul means to comfort us in our waiting and suffering as we long to be with God and be glorified by Him. He has just described believers as people who are called according to God's purpose. Now Scripture will talk about what that means. In doing so, this passage begins to introduce one of the most controversial and contentious ideas in all of theology: that of predestination.Paul begins by saying our calling to serve God's purpose goes all the way back to "before." He writes that God "foreknew" those who are now brothers and sisters of Jesus, because they have become the children of God by faith in Jesus. The word "foreknew" means that God, in some way or sense, knew each Christian before we knew Him.
Based on this sense in which He "foreknew" us, God predestined—determined, appointed, or ordained in advance—those who are saved to be conformed to the image of Jesus. Paul says it even more plainly in Ephesians 1:4, "He chose us in him [Christ] before the foundation of the world, that we should be holy and blameless before him."
Much of the controversy over this passage deals in whether or not God allows human free will to be a part of this choice, or whether God's actions are totally unilateral. So far as it goes for this specific statement, that level of detail is irrelevant. Chapter 9 will further discuss this concept, in ways which are more strongly influenced by how predestination is interpreted.
The bottom line of this particular verse is that we can stand secure. We can know, as those now in Christ, that God's purpose for us has always been that we should become like Christ. God had scheduled our entry into His family long before we were ever born. If God knew about us before we were born, and arranged for our salvation, He certainly knows about our trials and sufferings now, and what lies ahead. That should provide us with great comfort as we wait to be with our Father forever.