6:18
यदा विनियतं चित्तमात्मन्येवावतिष्ठते ।
निःस्पृहः सर्वकामेभ्यो युक्त इत्युच्यते तदा ॥६- १८॥
yadaa winiyataM chittamaatmanyewaawatiShThate ।
niHspRRihaH sarwakaamebhyo yukta ityuchyate tadaa ॥६- १८॥
Source: Automatic ITRANS Transliteration
When the restrained mind remains absorbed in the very self,
Uncovetous of every desire, then it is called union.
Source: Milind S. Pandit
A person is said to have achieved yoga, the union with the Self, when the perfectly disciplined mind gets freedom from all desires, and becomes absorbed in the Self alone.
When the yogi, by practice of yoga, disciplines his mental activities and becomes situated in Transcendence--devoid of all material desires--he is said to have attained yoga.
Source: Bhagavad Gita As It Is