Ephraim Urbach on the Jewish understanding of God knowing everything:
However, several of the earliest commentators of the Mishna already did not understand the phrase ha-kol safûy in the sense of ‘Everything is revealed and known from the outset’, but in the connotation ‘All that a man does in the innermost chambers, the Holy One, blessed be He, watches and observes’,11 and as Rabbi said, ‘Know what is above you—a seeing eye’ (M. ’Avot ii, 1); this explanation accords with the use of the stem safa in the idiom of the Tannaim. This verb does not signify knowledge of the future, but seeing that which exists and is present, like the Biblical usage ‘The eyes of the Lord keep watch [ sofôt] upon the evil and the good’ (Proverbs xv 3).
Urbach, Ephraim E.. The Sages: Their Concepts and Beliefs (Kindle Locations 5776-5783). . Kindle Edition.