Chapter 6 · The Yoga of Meditation · Krishna said
Bhagavad Gita 6.10 — Practice in solitude
योगी युञ्जीत सततमात्मानं रहसि स्थितः। एकाकी यतचित्तात्मा निराशीरपरिग्रहः ॥
yogī yuñjīta satatamātmānaṃ rahasi sthitaḥ | ekākī yatacittātmā nirāśīraparigrahaḥ ||
Meaning
A yogi should constantly unite the mind with the Self, staying alone in a quiet place, with body and mind controlled, free from longing and possessiveness.