Bhagavad Gita 5.21
He finds happiness in his own Self and enjoys eternal bliss, whose heart does not yearn for the contacts of the earth and whose Self is one with the Everlasting.
बाह्यस्पर्शेष्वसक्तात्मा विन्दत्यात्मनि यत्सुखम्।
स ब्रह्मयोगयुक्तात्मा सुखमक्षयमश्नुते॥bāhyasparśeṣvasaktātmā vindatyātmani yatsukham|
sa brahmayogayuktātmā sukhamakṣayamaśnute||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).