Bhagavad Gita 17.26

सद्भावे साधुभावे च सदित्येतत्प्रयुज्यते।प्रशस्ते कर्मणि तथा सच्छब्दः पार्थ युज्यते॥

sadbhāve sādhubhāve ca sadityetatprayujyate |praśaste karmaṇi tathā sacchabdaḥ pārtha yujyate ||

The word "Sat" is used to refer to reality and goodness; likewise, O Arjuna, the word "Sat" is used to refer to an auspicious act.

Sat' means Reality or the highest Good, and also, O Arjuna, it is used to denote an action of exceptional merit.

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