Bhagavad Gita 6.18

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

यदा विनियतं चित्तमात्मन्येवावतिष्ठते।
निःस्पृहः सर्वकामेभ्यो युक्त इत्युच्यते तदा॥

yadā viniyataṃ cittamātmanyevāvatiṣṭhate|
niḥspṛhaḥ sarvakāmebhyo yukta ityucyate tadā||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).