Parashas Eikev · Passuk 8:14
beware lestclest Heb. pen; moved down from v. 12 for clarity. your heart grow haughty and you forget the ETERNAL your God—who freed you from the land of Egypt, the house of bondage;
Torah Temimah points to Sotah 5a.
TT lemma: ורם לבבך ושכחת (unit 3 of 3).
English: Whence the warning against the arrogant? R’ Nachman bar Yitzchak said: From “and your heart grows haughty and you forget Hashem,” and from “Guard yourself lest you forget Hashem,” together with R’ Ila’a’s principle that wherever “hishamer” is stated it indicates a negative commandment.
Custom (lo ta’aseh against arrogance)
There is a scriptural warning against ga’avat ruach, built from the link between haughtiness and forgetting God.