Charles Ellicott Commentary Deuteronomy 29:4

"but Jehovah hath not given you a heart to know, and eyes to see, and ears to hear, unto this day." — Deuteronomy 29:4 (ASV)

Yet the Lord has not given you a heart to perceive. —“To mark the mercies of the Holy One, blessed be He! and to hold fast to Him” (Rashi). And so in Psalms 106:7, Our fathers understood not Your wonders in Egypt; they remembered not the multitude of Your mercies. (See also on Deuteronomy 31:16 and other verses.)