Bhagavad Gita · 6.15

युञ्जन्नेवं सदात्मानं योगी नियतमानसः।शान्तिं निर्वाणपरमां मत्संस्थामधिगच्छति॥

yuñjann evaṁ sadātmānaṁ yogī niyata-mānasaḥ śhāntiṁ nirvāṇa-paramāṁ mat-saṁsthām adhigachchhati

Thus, the yogi who constantly unites the mind with the Self, with a disciplined mind, attains the supreme peace of nirvana that abides in Me.

— Bhagavad Gita 6.15

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)