Bhagavad Gita 6.12 Chapter 6, Verse 12

तत्रैकाग्रं मनः कृत्वा यतचित्तेन्द्रियक्रियः ।
उपविश्यासने युञ्ज्याद्योगमात्मविशुद्धये ॥६.१२॥

tatraikāgraṃ manaḥ kṛtvā yatacittendriyakriyaḥ
upaviśyāsane yuñjyādyogamātmaviśuddhaye

Meaning

Sitting there, making the mind one-pointed and controlling the activities of the mind and senses, let him practise yoga for self-purification.

Newly written by Bhajan Dhun — scholarly review in progress.

Reference: Bhagavad Gita 6.12 (Chapter 6, The Yoga of Meditation (Atma Samyama Yoga), Verse 12)