The answer is very simple. It's all in the plain words of scripture. People generally try to avoid these scriptures, or they frowardly twist them to be more 'platable', as the blunt truth they present is quite frightening. But... the fear of God (the frightening realization of the power of his sovereignty) is the beginning of Wisdom, and we can learn to take comfort in this (if we are his sheep), such resting (Sabbath) being the very essence of faith ("Trust and obey. God is in control.")
Isaiah 56:9-11
9 Remember the former things of old: for I am God, and there is none else; I am God, and there is none like me,
10
Declaring the end from the beginning, and from ancient times the things that are not yet done, saying, My counsel shall stand, and I will do all my pleasure:
11 Calling a ravenous bird from the east, the man that executeth my counsel from a far country: yea, I have spoken it, I will also bring it to pass; I have purposed it, I will also do it.
Isaiah 45:7
"I form the light, and create darkness: I make peace, and create evil: I the LORD do all these things."
Amos 3:6
"Shall a trumpet be blown in the city, and the people not be afraid? shall there be evil in a city, and the LORD hath not done it?"
We are God's robots. Free-will is the lying doctrine of Babylon, by which man blasphemes the sovereignty of God, and declares himself to be his own god, the dictator of his own destiny. However, the catch is that God even destines men to blaspheme his authority, so he can destroy them.
John 12:40
"He hath blinded their eyes, and hardened their heart; that they should not see with their eyes, nor understand with their heart, and be converted, and I should heal them."
Romans 9:22
"What if God, willing to shew his wrath, and to make his power known, endured with much longsuffering the
vessels of wrath fitted to destruction"
So, the God who declares all things from beginning to end has also declared, from the beginning, those who would go to hell, as well as the 'decisions' they would make which would result in this.
God controls everything, including the acts of the Babylonian soldiers who bashed the brains out of the children of Jerusalem, raped the women and pulled the remaining population into captivity. Does God sin in this? No. He is not subject to the laws of good and evil; that law was created by him, FOR US.
He can do what he wants. After all, he's God.
Our acts do not direct or change the future. Rather they are simply the plan of God which has already been set.