Bhagavad Gita 4.28

4.28 Others again offer wealth, austerity and Yoga as sacrifice, while the ascetics of self-restraint and rigid vows offer study of scriptures and knowledge as sacrifice.

Having accepted strict vows, some become enlightened by sacrificing their possessions, and others by performing severe austerities, by practicing the yoga of eightfold mysticism, or by studying the Vedas to advance in transcendental knowledge.