The Vedic Samhitas contain references to ascetics , while ascetic practices ( tapas ) are referenced in the ( ( Brahmana ) ) ( 900 to 500 BCE ) , early commentaries on the Vedas . The Vedic Samhitas contain references to ascetics , while ascetic practices ( `` tapas '' ) are referenced in the ( ( Brahmana ) ) ( 900 to 500 BCE ) , early commentaries on the Vedas .