Evil is necessary for free will to exist. No choice between good and evil, no free will.
God is outside time, but for God there is no past, present and future. I'll give you a few line from Milton's Paradise Lost regarding omniscience and really read this carefully;
For man will heark'n to his (the devil's)glozing lyes,
And easily transgress the sole Command,
Sole pledge of his obedience: So will fall, [ 95 ]
Hee and his faithless Progenie: whose fault?
Whose but his own? ingrate, he had of mee
All he could have; I made him just and right,
Sufficient to have stood, though free to fall.
Freely they stood who stood, and fell who fell.
Not free, what proof could they have givn sincere
Of true allegiance, constant Faith or Love,
Where onely what they needs must do, appeard, [ 105 ]
Not what they would? what praise could they receive?
What pleasure I from such obedience paid,
When Will and Reason (Reason also is choice)
Useless and vain, of freedom both despoild,
Made passive both, had servd necessitie, [ 110 ]
Not mee.
They therefore as to right belongd,
So were created, nor can justly accuse
Their maker, or their making, or their Fate,
As if predestination over-rul'd
Their will, dispos'd by absolute Decree [ 115 ]
Or high foreknowledge; they themselves decreed
Thir own revolt, not I: if I foreknew,
Foreknowledge had no influence on their fault,
They trespass, Authors to themselves in all
Both what they judge and what they choose; for so
I formd them free, and free they must remain