Bhagavad Gita 6.18

यदा विनियतं चित्तमात्मन्येवावतिष्ठते।निःस्पृहः सर्वकामेभ्यो युक्त इत्युच्यते तदा॥

yadā viniyataṃ cittamātmanyevāvatiṣṭhate |niḥspṛhaḥ sarvakāmebhyo yukta ityucyate tadā ||

When the perfectly controlled mind rests in the Self alone, free from longing for any of the objects of desire, then it is said, 'He is united'.

When the mind is completely controlled, centered in the Self, and free from all earthly desires, then the man is truly spiritual.

Our plain-language meaning of this verse is waiting for scholar review.