From the new blog Why I am a Heretic:

The Lord said to Moses, “You are about to rest with your fathers, and these people will soon commit adultery with the foreign gods of the land they are entering. They will abandon Me and break the covenant I have made with them.” (Deuteronomy 31:16, HCSB)

The above verse a Classic Theist might state God knows all future decisions from either a simple foreknowledge point of view, or exhaustive foreknowledge.

But then we come to this verse:

“And when many troubles and afflictions come to them, this song will testify against them, because their descendants will not have forgotten it. For I know what they are prone to do, even before I bring them into the land I swore to give them.” (Deuteronomy 31:21, HCSB) [emphasis mine]

God knows what they are ‘prone’ to do, or some other translations state that God knows their ‘imaginations’ / ‘strong desire and purposes’ / ‘know how they think’.

The Hebrew term is יִצְר֗וֹ, or ‘yetser’ , which from Strong’s Exhaustive Concordance states: a form; figuratively, conception (i.e. Purpose) — frame, thing framed, imagination, mind, work.

God knows our hearts and intentions intimately because he knows US intimately as our Creator and heavenly Father. He doesn’t require exhaustive foreknowledge, or even simple foreknowledge to know these things.