Bhagavad Gita 17.26

संगते साधुभावे च सदित्येतत्प्रयुज्यते |
पराणे कर्माणि तथा सच्चबद: पार्थ युज्यते

Translation

The word “Sat” means eternal existence and goodness. O Arjun, it is also used to describe an auspicious action.