Deuteronomy 29:4 - Ellicott's Commentary On The Whole Bible

Yet the Lord hath not given you an heart to perceive. — “To mark the mercies of the Holy One, blessed be He! and to cleave unto Him” (Rashi). And so in Psalms 106:7, “Our fathers understood not Thy wonders in Egypt; they remembered not the multitude of Thy mercies.” (See also on Deuteronomy 31:16, &c.)