Rabbi [Judah Hanassi] would say: Which is the correct path for man to choose? Whatever is harmonious for the one who does it, and harmonious for mankind.
Ethics of the Fathers 2:1
If I am not for myself, who is for me?
And if I am only for myself, what am I?
Ethics of the Fathers, 1:14
Rabbon Gamliel’s son, Shimon, would say: All my life I have been raised among the wise, and I have found nothing better for the body than silence...
Ethics of the Fathers, 1:17
All quotes pulled from here. Although I should add for those who are interested this is just one site that I frequent.
Ben Zoma would say: Who is wise? One who learns from every man. As it is written: “From all my teachers I have grown wise, for Your testimonials (eidosecha) are my meditation.”
Ethics of the Fathers, 4:1