B.G 18.04
निश्चयं शृृणु मे तत्र त्यागे भरतसत्तम। त्यागो हि पुरुषव्याघ्र त्रिविधः सम्प्रकीर्तितः ॥४॥
niścayaṃ śṛṇu me tatra tyāge bharatasattama। tyāgo hi puruṣavyāghra trividhaḥ samprakīrtitaḥ ॥4॥
[निश्चयं (niścayam) - certainty; शृणु (śṛṇu) - hear; मे (me) - my; तत्र (tatra) - there; त्यागे (tyāge) - in relinquishment; भरतसत्तम (bharatasattama) - O best of the Bharatas; त्यागः (tyāgaḥ) - relinquishment; हि (hi) - indeed; पुरुषव्याघ्र (puruṣavyāghra) - O tiger among men; त्रिविधः (trividhaḥ) - threefold; सम्प्रकीर्तितः (samprakīrtitaḥ) - is declared;]
Listen to my definitive conclusion on relinguishment (tyāga), O best of the Bharatas. Relinquishment is indeed declared to be of three kinds, O tiger among men.
Gīta Bhāshya 18.04
Definitive conclusions regarding relinquishment (tyāga) is explained further.
तत्प्रकारं चाह - निश्चयमित्यादिना ॥४॥
tatprakāraṃ cāha - niścayamityādinā ॥4॥
[तत् (tat) - that; प्रकारं (prakāraṃ) - manner; च (ca) - and; आह (āha) - said; निश्चयम् (niścayam) - certainty; इत्यादिना (ityādinā) - and so on;]
The conept (of relinquishment) is described by the verse 'niścayam', i.e. with certainty and so on.