“The mind should not be allowed to enjoy the bliss that arises out of samādhi. It should be freed from attachment to such happiness through the exercise of discrimination. If the mind, once attaining to the state of steadiness, seeks externality, then it should be unified with the Ātman again, with effort.” —Māṇḍūkya Upaniṣad Kārikā 3.45  
“The aspirant should not taste the happiness experienced by yogīs seeking after samādhi. He is not to be attached to that happiness. What then should he do? He should become unattached to such happiness by knowledge through discrimination, and think that whatever happiness is experienced is false—conjured up by ignorance. Thus the mind should be turned back from such happiness. When, once being withdrawn from happiness and fixed on the state of steadiness, if the mind again manifests its outgoing propensities, then control it by adopting the above-mentioned means; and with great care, make it one with Ātman—make the mind attain the condition of pure existence and thought.”  — Śaṅkarācārya’s Commentary ơn Māṇḍūkya Upaniṣad Kārikā 3.45