Bhagavad Gita Chapter 17 Verse 26

Gita 17.26

सद्भावे, साधुभावे, च, सत्, इति, एतत्, प्रयुज्यते,
प्रशस्ते, कर्मणि, तथा, सत्, शब्दः, पार्थ, युज्यते।।26।।

Gita 17.26

Sad’bhaave, saadhubhaave, ch, sat’, iti, etat’, pryujyate,
Prshaste, karmni, tatha, sat’, shabdH, paarth, yujyate ||26||

Translation: (Sat’) Sat’ (iti) this Saarnaam at the end of Tat’ mantra (etat’) with the name of this very Purna Parmatma (sad’bhaave) in true sense (ch) and (saadhubhaave) in supreme sense (pryujyate) is used (tatha) and (paarth) Oh Paarth! (prshaste) superior (karmni) in act only (sat’ shabdH) Sat’ Shabd i.e. Saarnaam (yujyate) is used; i.e. is added at the end of the aforesaid two mantras Om’ and Tat’. (26)

Translation: ‘Sat’’- this Saarnaam is used in true sense and in supreme sense at the end of Tat’ mantra with the name of this very Purna Parmatma, and Oh Paarth, Sat’ Shabd i.e. Saarnaam is only used in a superior act; i.e. is added at the end of the aforesaid two mantras Om’ and Tat’.