Mahabharata 12.315.50

सम्यगन्वीक्षतां बुद्ध्या शान्तयाध्यात्मनित्ययाध्यानाभ्यासाभिरामाणां योऽमृतत्वाय कल्पते

samyaganvīkṣatāṃ buddhyā śāntayādhyātmanityayādhyānābhyāsābhirāmāṇāṃ yo'mṛtatvāya kalpate

Our plain-language meaning of this verse is waiting for scholar review.