Jīvaka Sutta, Aṅguttaranikāya

[Bhikkhu Pesala]

Another discourse to Jīvaka is found in the Book of Eights in the Gradual Sayings or Numerical Discourses. 

The topic is how one becomes a lay disciple, a virtuous lay disciple, and how one practises for one's own benefit and the benefit of others.

[Mkoll]

Related to that sutta is Chavālātasutta (AN 4.95) where the Buddha teaches that the one who practices for their own benefit as well as others is the highest of the 4 types of individuals taught in the sutta. This is a good sutta to support putting to rest the unfortunate misconception that Buddhism, especially Theravada, is "selfish."