Design
सद्भावे साधुभावे च सदित्येतत्प्रयुज्यते |
प्रशस्ते कर्मणि तथा सच्छब्द पार्थ युज्यते || 26||
यज्ञे तपसि दाने च स्थिति सदिति चोच्यते |
कर्म चैव तदर्थीयं सदित्येवाभिधीयते || 27||
Design

17.26-27
The word “Sat” means eternal existence and goodness. O Arjun, it is also used to describe an auspicious action. Being established in the performance of sacrifice, penance, and charity, is also described by the word “Sat.” And so any act for such purposes is named “Sat.”

Now the auspiciousness of the word “Sat” is being glorified by Shree Krishna. This word
Sat
has many connotations, and the above two verses describe some of these.
Sat
is used to mean perpetual goodness and virtue. In addition, auspicious performance of sacrifice, austerity, and charity is also described as
Sat
.
Sat
also means that which always exists i.e., it is an eternal truth. The Śhrīmad Bhāgavatam states
satya-vrataṁ satya-paraṁ tri-satyaṁ
satyasya yoniṁ nihitaṁ cha satye
satyasya satyam ṛita-satya-netraṁ
satyātmakaṁ tvāṁ śharaṇaṁ prapannāḥ (10.2.26)
[v8]
“O Lord, your vow is true, for not only are you the Supreme Truth, but you are also the truth in the three phases of the cosmic manifestation—creation, maintenance, and dissolution. You are the origin of all that is true, and you are also its end. You are the essence of all truth, and you are also the eyes by which the truth is seen. Therefore, we surrender unto you, the
Sat
i.e., Supreme Absolute Truth. Kindly give us protection.”