Chapter 6 · The Yoga of Meditation · Krishna said
Bhagavad Gita 6.27 — The highest joy
प्रशान्तमनसं ह्येनं योगिनं सुखमुत्तमम्। उपैति शान्तरजसं ब्रह्मभूतमकल्मषम् ॥
praśāntamanasaṃ hyenaṃ yoginaṃ sukhamuttamam | upaiti śāntarajasaṃ brahmabhūtamakalmaṣam ||
Meaning
Supreme joy comes to the yogi whose mind is fully calm, whose restlessness has settled, who is free of sin and has become one with Brahman.