Did God plan or know Adam and Eve were going to sin? Genesis 6: 5-6 says: “The LORD saw how great man’s wickedness on the earth had become, and that every inclination of the thoughts of his heart was only evil all the time. The LORD was grieved that he had made man on the earth, and his heart was filled with pain.” Some theists have suggested, based on their interpretation of certain biblical passages, that God actually preordained evil and the fall of man before it actually happened, but that would make this passage seem nonsensical and overly dramatic by the writers if they understand this to be true. Why would God grieve something He had intended all along as part of His plan? Do God’s predetermined actions grieve Him?
Not only did God not plan or foreordain sin, God not having foreknowledge of an unknown future seems to give more integrity to passages that speak of God grieving, relenting, giving another chance, etc. Is a fixed future required from a biblical viewpoint? If God already knows what someone is going to do, one can legitimately ask if there is genuine freedom. Are they truly free to do anything different? Traditionalists may argue that passages such as Genesis 6 teach God was aware of what had changed and chose to act emotionally in accordance with the new situation. We know our loved ones are going to die with certainty, but we still have feelings when that day comes. If the future can be known, we can say God grieves because man either sins or obeys and this still can impact God at the moment.
We could say God knows what is going to happen but still engages with us; it simply is harder to relate to. But, we do not have to argue God knows the unknowable to somehow protect His character. God can still be omniscient (all knowing) and not know the future, if the future is not fixed. God does know what is knowable. He even knows what we are thinking. He is superior to humans in knowing all the possibilities of decisions that can be made by others and fully prepared for what He will do. Too, God knows what He will do regardless of human decisions, such as the miraculous birth of Jesus. It seems to me it can be argued the biblical writers did not know anything about the future being predetermined or known, when we read passages such as Genesis 6.
What God May Really Be Like - Misbeliefs About God 