When he attains the knowledge of the supreme Brahman, which is the only medicine for birth, old age, sorrow, disease, etc., then that yogi attains in the form of Brahman.

यदा सर्वाणि भूतानि स्वात्मन्येवाभि पश्यति ।

एकीभूतः परेणासौ तदा भवति केवलः ॥

~ When he sees other beings and things in his aatma, then that yogi, who is one with the Supreme Soul, having no control by others, attains the Kevali Bhav.

यदा सर्वे प्रमुच्यन्ते कामा येऽस्य हृदि स्थिताः ।

तदासावमृतीभूतः क्षेमं गच्छति पण्डितः

~ When all desires vanish from the heart of that yogi, then he attains the wisdom of immortality and becomes partaker of the supreme welfare.

यदा भूतपृथग्भावमेकस्थमनुपश्यति ।

तत एव च विस्तारं ब्रह्म सम्पद्यते तदा ॥

~ When the yogi has a vision of oneness of various beings, then the same (vision) expands and he attains the brahman consciousness.

यदा पश्यति चात्मानं केवलं परमार्थतः । मायामात्रं जगत्कृत्स्नं तदा भवति निर्वृतः ॥

~ When the yogi truly begins to see only the existence of the aatma and knows about the illusion of the whole (external) world, then he attains supreme peace.

यदा जन्मजरादुःखव्याधीनामेकभेषजम् ।

केवलं ब्रह्मविज्ञानं जायतेऽसौ तदा शिवः ॥

~ When he attains the knowledge of the supreme Brahman, which is the only medicine for birth, old age, sorrow, disease, etc., then that yogi attains in the form of Brahman.

यथा नदी नदा लोके सागरेणैकतां ययुः ।

तद्वदात्माक्षरेणासौ निष्कलेनैकतां व्रजेत् ॥

~ As the (different) rivers and streams of the world become one by going into the ocean, so the soul merges into that Akshara, the immutable Supreme Being.

Sri Rama Gita