Bhagavad Gita · Dhyana Yoga (Atma-samyama Yoga)Chapter 6, Shloka 14 (6.14)

Shankaracharya. Praśāntātmā prakarṣeṇa śāntaḥ ātmā antaḥkaraṇaṃ yasya; vigatabhīḥ vigata-bhayaḥ; brahmacāri-vrate … brahmacaryaṃ guru-śuśrūṣā-bhikṣānna-bhukty-ādi — the vow of the brahmachari, that is, brahmacharya, service to the guru, eating food received as alms and so on; mac-cittaḥ mayi parameśvare cittaṃ yasya. To explain "mat-paraḥ", a comparison: kaścit rāgī strī-cittaḥ na tu striyam eva paratvena gṛhṇāti kiṃ tarhi rājānaṃ mahādevaṃ vā, ayaṃ tu mac-citto mat-paraś ca — a passionate man may think of a woman, but does not regard her as "supreme" (he regards the king or Mahadeva as supreme); this yogi both keeps the mind on Me and regards Me as supreme.

Acharya Ramanuja (6.13–6.14 combined). Praśāntātmā atyanta-nirvṛta-manāḥ — a mind utterly content; vigata-bhīḥ; brahmacarya-yuktaḥ; mac-citto yuktaḥ avahitaḥ mat-para āsīta mām eva cintayan āsīta — let one sit attentive, regarding Me alone as supreme, contemplating Me alone.