Manava Dharmashastra 2.28

2.28

svādhyāyena vratair homais traividyenejyayā sutaiḥ
mahāyajñaiś ca yajñaiś ca brāhmīyaṃ kriyate tanuḥ //

By the study of the Veda, by vows, by burnt oblations, by (the recitation of) sacred texts, by the (acquisition of the) threefold sacred science, by offering (to the gods, Rishis, and manes), by (the procreation of) sons, by the great sacrifices, and by (Srauta) rites this (human) body is made fit for (union with) Brahman.