Śrīmad-Bhāgavatam 3.12.41
SB 3.12.41
Open the full passageSanskrit
vidyā dānaṁ tapaḥ satyaṁ dharmasyeti padāni ca āśramāṁś ca yathā-saṅkhyam asṛjat saha vṛttibhiḥ
Translation
Education, charity, penance and truth are said to be the four legs of religion, and to learn this there are four orders of life with different classifications of castes according to vocation. Brahmā created all these in systematic order.