Yājñavalkya Śikṣā 171

171

śuśrūṣārahitā vidyā api medhāguṇairyutā
bandhyeva yuvatī tasya na vidyā phalinī bhavet

Knowledge devoid of service [to the teacher], even though accompanied by virtues of intellect, / is like a barren young woman: his knowledge does not bear fruit.