yadā viniyataṁ chittam ātmanyevāvatiṣhṭhate
niḥspṛihaḥ sarva-kāmebhyo yukta ityuchyate tadā||18||

Meaning : When the mind is completely controlled and remains focused only on the Self, and the person is free from all desires for worldly pleasures, then they are said to be truly united in Yoga.