ब्रह्मभूतः प्रसन्नात्मा न शोचति न काङ्क्षति। समः सर्वेषु भूतेषु मद्भक्तिं लभते पराम् ॥

brahma-bhūtaḥ prasannātmā na śhochati na kāṅkṣhati samaḥ sarveṣhu bhūteṣhu mad-bhaktiṁ labhate parām

Becoming the Eternal, serene in the Self, he neither grieveth nor desireth; the same to all beings, he obtaineth supreme devotion unto Me.

In plain words: Krishna says a person who has become one with the Eternal is calm inside. They no longer grieve or crave. They see all beings as equal and gain the highest love for God.