ואל תאמין בעצמך עד יום מותך

“Do not trust in yourself until the day you die.”

Stay humble and vigilant about your own character; certainty about one's own righteousness is dangerous.

— Traditional Israel Wisdom, Israel

Source: Hillel the Elder, Pirkei Avot (Ethics of the Fathers) 2:5, Mishnah, c. 200 CE