B.G 17.27 and 28

यज्ञे तपसि दाने च स्थितिः सदिति चोच्यते। कर्म चैव तदर्थीयं सदित्येवाभिधीयते ॥२७॥

Steadiness in sacrifice, austerity, and charity is referred to as 'sat', i.e. real, and so also is the action taken for that purpose.

अश्रद्धया हुतं दत्तं तपस्तप्तं कृतं च यत्। असदित्युच्यते पार्थ न च तत् प्रेत्य नो इह ॥२८॥

O son of Pritha, whatever is offered, given, or performed without faith is considered 'asat', i.e. unreal. It benefits us neither in this life nor in the afterlife.

Gīta Tātparya 17.27 and 28

The sound 'Om tat sat' is renowned as the name of Lord Vishnu. A mantra recited without understanding its meaning is ineffective and serves only to protect one's ego. Therefore, the true meaning of the mantra should be understood. For the purpose of attaining the fruits of sāttvika actions, one must act with devotion and remembrance of the divine. The sentiment is - anything other than the truth is false.

तत्सम्बन्धित्वादेव कर्मादि सत्। ओं तत्सदिति नाम्नां विष्णौः प्रसिद्धत्वात्।

Because of its connection with THAT, actions and such austerities are called 'sat', i.e. real. The sound 'Om tat sat' is thus renowned as the name of Lord Vishnu.

"स्रवत्यनोङ्कृतं ब्रह्म परस्ताच्च विशीर्यते। अनोऽङ्कृतं आसुरं कर्म"

"The breath marked with Om, flows beyond and disintegrates into Brahman. The unmarked breath is considered a demonic action."

इति श्रुतेः अनोङ्कृतस्य आसुरत्वप्रसिद्धेः।

Thus, it is known from the scriptures about the fame of demon hood of the unmarked.

"अनर्थज्ञोदितो मन्त्रो निरर्थस्त्राति मानतः। यन्मन्त्रस्तेन कथितो मन्त्रार्थो ज्ञेय एव तत्॥"

"A mantra recited without understanding its meaning is ineffective and only serves to protect one's ego. Therefore, the true meaning of the mantra should be understood."

इति पैङ्गिश्रुतेश्च।

- stated thus in the Paiṅgi Vedic testimonial.

तदर्थत्वेन फलानभिसन्धिपूर्वककर्मण एव सात्विकत्वाच्च। तद्भक्त्या तत्स्मरणपूर्वकमेव सदन्यदसदेवेति भावः। राजसस्यापि असदन्तर्भाव एव। विष्णुश्रद्धारहितत्वात्॥

For the purpose of attaining the fruits of actions, which are sāttvika, one must act with devotion and remembrance of the divine. The sentiment is that anything other than the truth is false. Even those with a rājasa nature include falsehood due to a lack of faith in Viṣṇu.

"सात्त्विकं मोक्षदं कर्म राजसं सृतिदुःखदम्। तामसं पातदं ज्ञेयं तत्कुर्यात् कर्म वैष्णवम्॥"

"Actions performed in the mode of goodness lead to liberation, those in the mode of passion lead to sorrow in the cycle of birth and death, and those in the mode of ignorance lead to downfall. Therefore, one should perform actions that are related to Vishnu."

इत्याग्नेये॥

- stated thus in the Agni Purana.

॥ इति श्रीमदानन्दतीर्थभगवत्पादाचार्यविरचिते श्रीभगवद्गीतातात्पर्यनिर्णये सप्तदशोध्यायः ॥

Thus ends the seventeenth chapter of the Śrī Bhagavad Gītā purport, composed by Ānandatīrtha Bhagavatpāda Ācārya.

॥ ओं तत्सदिति श्रीमद्भगवद्गीतासु उपनिषत्सु ब्रह्मविद्यायां योगशास्त्रे श्रीकृष्णार्जुनसंवादे श्रद्धात्रयविभागयोगो नाम सप्तदशोध्यायः ॥

'Om Tat Sat'. Thus, the seventeenth chapter of the Bhagavad Gita, named 'The Yoga of the Division of the Threefold Faith', is declared in the Upanishads, in the knowledge of Brahman, and in the science of Yoga, through the dialogue between Sri Krishna and Arjuna ends.