B.G 2.39
एषा तेऽभिहिता साङ्ख्ये बुद्धिर्योगे त्विमां शृणु। बुद्ध्या युक्तो यया पार्थ कर्मबन्धं प्रहास्यसि ॥२-३९॥
eṣā te'bhihitā sāṅkhye buddhiryoge tvimāṁ śar̥ṇu। buddhyā yukto yayā pārtha karmabandhaṁ prahāsyasi ॥2-39॥
The teaching so far imparted to you is called 'Sānkhya', the accurate and certain knowledge. O Partha, listen now to the exposition of 'Yōga', the means of obtaining that certain knowledge i.e. wisdom, equipped with which you will overcome bondage to the results of all actions.
Gīta Tātparya 2.39
Gita refers to the original Sānkhya and Yōga (parama-sānkhya and parama-yōga) which means "accurate and certain knowledge" and "means to attain it" respectively. It is not the same as the prevailing independent philosophies of Sānkhya and Yōga.
Accurate certain knowledge is 'Sānkhya' . 'Yōga' is means to that knowledge and is the practical solution.
"Understanding of correct governing principles is 'Sāmkhya'. 'Yōga' is the means to achieve it."
- it is stated thus in "Shabdanirnaya" dictionary.
"Brahmatarka is a text of logic narrated by lord Vishnu himself. Nyāya philosophy of Akshapada, Vaisheshika philosophy of Kanada, and Sānkhya and Yōga philosophies are motivated, i.e. do not provide correct Vedic knowledge. Buddhism and Pāshupata based agamas are false doctrines. People know this well. Mīmāsa philosophy can be interpreted in three ways: pro Brahman, or pro Daivi, i.e, exalting the feminine prakrti, or pro ritualistic. Brahmatarka and Mīmāmsa philosophies must be studied to obtain knowledge. Other doctrines are opposed to Vedic knowledge and the wise do not follow them."
Thus, independent Sāmkhya and Yōga philosophies are forbidden in Nārada purāna. The independent philosophies of Sānkhya and Yōga advocate the non-existence of God, while the Bhagavad Gita asserts the existence of God. Both Sānkhya and Yōga advocate non killing and passivity faced with injustice, as killing leads to destruction as per their doctrine. But Bhagavad Gita advocates the rightful war as a way to liberation by forsaking bondage to results of action.
The topics stated by Supreme Sānkhya and Yōga as per the earlier stated understanding (i.e. Sānkhya = accurate and certain knowledge; Yōga = means to attain that knowledge) are not opposed to Bhagavad Gita.
Note: Sānkhya, Yōga, Nyāya, and Vaisheshka darshanas are considered to be motivated and not accurate in their current form. The original Darshanas of Sānkhya and Yōga are termed as "Parama Sānkhya and Yōga" and are accepted. Buddhism and Pāshupata āgama are rejected as false doctrines. Mīmamsa is accepted, though has different layers of interpretation.
