Bhagavatapurana 3.12.41

3.12.41

vidyā dānaṃ tapaḥ satyaṃ dharmasyeti padāni ca /
āśramāṃś ca yathā-saṅkhyam asṛjat saha vṛttibhiḥ //

41. 42. Then He produced the four feet of Dharma viz, Learning, or, Knowledge, Charitable gifts, Tapas, Satya or Truthfulness and the Asramas with their respective functions or duties viz. Savitra (the study of Gayatri), Prajapatya (vows to be observed for a year), Brahma (study of the Vedas to the end) and Brihat (the great vow of celibacy), agriculture, help given to Sacrificial acts, Saleena (living by asking for others' help) and Silonchcha (gleaning of scattered corn)—all these to be followed by those that lead a house-holder's life.