Bhagavad Gita 15.4
Beyond lies the path, from which, once found, there is no return. This is the Primal God from whom this ancient creation has sprung.
ततः पदं तत्परिमार्गितव्य यस्मिन्गता न निवर्तन्ति भूयः।तमेव चाद्यं पुरुषं प्रपद्ये यतः प्रवृत्तिः प्रसृता पुराणी॥tataḥ padaṃ tatparimārgitavya yasmingatā na nivartanti bhūyaḥ|tameva cādyaṃ puruṣaṃ prapadye yataḥ pravṛttiḥ prasṛtā purāṇī||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).