Bhagavad Gita Chapter 18 Verse 7
भगवद् गीता अध्याय 18 श्लोक 7

नियतस्य तु संन्यासः कर्मणो नोपपद्यते।
मोहात्तस्य परित्यागस्तामसः परिकीर्तितः।।18.7।।



English Translation - Swami Sivananda
18.7 Verily the renunciation of obligatory action is not proper; the abandonment of the same from delusion is declared to be Tamasic.


English Translation of Sanskrit Commentary By Sri Shankaracharya's
18.7 Therefore, sannyasah, the abandoning; niyatasya tu karmanah, of the daily obligatory acts, by the seeker of Liberation who is as yet unenlightened and is fit for rites and duites; na apapadyate, is not justifiable, because what is desired is the purification of unenlightened persons. Parityagah, giving up; tasya, of that, of the daily obligatory duty; mohat, through delusion, through ignorance; parikirtitah, is declared; to be tamasah, based on tamas.
Niyata is that duty which must be performed. That an act is niyata (obligatory) and it is relinished is contradictory. Therefore the giving up of that through delusion is declared to be based on tamas, for delusion is tamas.
Besides,


Transliteration Bhagavad Gita 18.7Niyatasya tu sannyaasah karmano nopapadyate;
Mohaattasya parityaagas taamasah parikeertitah.


Word Meanings Bhagavad Gita 18.7niyatasya—of prescribed duties; tu—but; sanyāsaḥ—renunciation; karmaṇaḥ—actions; na—never; upapadyate—to be performed; mohāt—deluded; tasya—of that; parityāgaḥ—renunciation; tāmasaḥ—in the mode of ignorance; parikīrtitaḥ—has been declared