This is the beauty of veda that even if people don't understand the meaning of the sutras, they still feel it. This sutras occur in a section called "Dahara Vidya" of the MahaNarayano Upanishad.
The first line says: Neither by actions, nor through progeny and wealth, but by renunciation alone is immortality attained
The second line says: This State is far beyond the highest heaven, and the sages perceive it,hidden in the cave of the heart, shining brilliantly therein.
The third line says: Those, who have a clear understanding of the principles of science of Vedanta,who have purified themselves by means of the yoga of renunciation,and who are (thus) established in the state of supreme are totally liberated in the Brahman.
Read Gita, where Bhagawan talks about karma sanyas and he shows the path of mukti.