The works of Ādi Śaṅkarācārya

Sanatsujātīyam

p. 311

p. 311

भावयन्षाडिन्द्रियाणि संनियम्य निश्चलः ॥१॥

In plain words

Holding the six senses in check, steady in contemplation, he does not waver.

Close to the Sanskrit

Contemplating, having fully restrained the six senses, [he remains] unwavering.