Without foreknowledge of free acts God would not be omniscient
Certainly, if God does not know every future thing from eternity, but is ignorant of what creatures will freely do, omniscience can no longer be ascribed to him.
Nor can he truly be said to know all things, since some things would be hidden from his knowledge.
Latin
VIII. Et certe si Deus ab aeterno futura quaelibet non praescit, sed ignorat ea quae sunt a creaturis libere agenda, omniscientia Deo amplius tribuenda non est; neque vere dici potest omnia scire, siquidem nonnulla sunt quae latent ejus scientiam.