God knows all things.
God knows the all the freely chosen actions of those whom he WILL create (in our time) but has not yet created.
He actively wills the existence of those whose lives are forseeable.
THerefore, in view of his omniscience he predestines all he creates to their ultimate end, for they have no choice but to use their free will in the manner in which God has forseen.
THerefore, the freedom of our acts is not compromised by predestination, and God’s sovreignty is maintained ins spite of our personal freedom.
AS Aquinas teaches, God has predestined all our choices that we freely make. For on the one hand we could not do otherwise than what God has forseen we freely do.
But we are created free.
Paradox, not oxymoron.