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Predestination and free will

If God knows everything in advance, and if nothing can happen without his permission, it follows that all the evils and terrible events are already pre ordained. Why does God not prevent children and the weak from suffering so much and how much is in the hands of man when everything is pre determined in any case?

Answer

These are two questions:
If nothing can happen without God’s permission, why does He allow terrible events to happen? The answer to it is two-fold: This life is a trial and therefore He does not force people to do what He wants them to do. Had He forced them to do what He expected from them, it would have been be a trial. To make this life a meaningful trial, He has allowed humans to do what they want to in those domains of their lives where they are being tested. His permission to humans to do what they would choose to should not be taken to mean that what they do as a consequence of this freedom is what He likes. He tolerates some of the terrible things people do because of a higher purpose: He wants to ensure that the worldly life is a genuine trial.
God tolerates the evil that is happening in this world also because He knows that He has made adequate arrangements for those who suffer here to be compensated and for those who inflict pain to others to be properly punished. Although at times the compensation and punishment is partly experienced in this life as well, the real reward and punishment will come in the next life.
The other question is this: If God knows everything in advance, it follows that everything is already ordained. Why is it so and how much is in the hands of man? The answer to this is that we know God through His attributes which are all infinite. If His attributes were not infinite, He would not be God. He is infinitely knowledgeable, just, mighty, wise, merciful and so on. Not only that, all His attributes function simultaneously. It is not that when He is knowledgeable, He is not just or vice versa. He is both and all other things at the same time.
His infinite knowledge enables Him to know everything about the future and His infinite justice causes Him to not put humans through an unfair trial where they are punished for what they are not guilty of. The two can happen if we understand that even though God knows what we will do in the future, He also knows that whatever we do, will not always be forced upon us by His prior knowledge but we will do it voluntarily, willingly. And if at all an act would be imposed on us, we will not be accountable for doing it.
We cannot fully grasp what I have written in the previous paragraph, not because it is incorrect or impossible, but because like all other faculties, our intellect too is limited. Just as a student in a primary school who does not understand what a PhD in Mathematics has mentioned in his equation cannot claim that it is wrong because of his inability to understand it, we cannot sometimes understand some of God’s ways of doing things too. In order to help us appreciate that the fore knowledge of future events is a reality, God has arranged for some of us to see clear dreams of some of the things that will happen in the future. How could those dreams be seen had the future not been known to the One who arranged experiencing of those dreams? The remarkable fact is that some of the visions of the future people see in their dreams are actualized as a consequence of an interplay of many decisions which some people take independently without apparently being forced by anyone.