If I am not for myself, who will be for me? And if I am only for myself, what am I? And if not now — when?

Hillel (1st C. BC-1st C. AD) Jewish sage, rabbi

Talmud, Mishnah, “Pirkay Avot [Chapters of the Fathers],” Aboth 1:14 [tr. Rosten (1972)]