Where in the hell does it say that in the bible?God has set a certain time for the tribulation because he wants to give sinners a last chance to repent before the day of judgement. God in order to have meaningful relationship with the angels gave them free will, but unfortunately, Satan decided to rebel. 1/3 of the angels joined him. Then he convinced Eve to eat the forbidden fruit and she convinced Adam and so sin entered the world. Sinners have the chance throughout their life to repent, but many choose not to and therefore go to hell.
Also free will and omniscience are mutually exclusive. If you know what will happen, then there can't be free will. If there is free will, you can't know what's going to happen.
I should stop with this derail probably but I really enjoy this topic.