Rashi on Exodus 34:3/רש"י על שמות ל״ד:ג׳

1ואיש לא יעלה עמך AND NO MAN SHALL GO UP WITH THEE — Because the first tablets were given amidst great noises and alarms and a vast assembly the “evil eye” had power over them (they did not endure) — there is no finer quality than to be unostentatious! (Midrash Tanchuma 3:9:31).