B.G 3.03

श्रीभगवानुवाच-
लोकेस्मिन् द्विविधा निष्ठा पुरा प्रोक्ता मयानघ। ज्ञानयोगेन साङ्ख्यानां कर्मयोगेन योगिनां ॥३॥

śrībhagavānuvāca-
lōkēsmin dvividhā niṣṭhā purā prōktā mayānagha। jñānayōgēna sāṅkhyānāṁ karmayōgēna yōgināṁ ॥3॥

The Lord said:
Oh sinless one, In this world, two types of 'niṣṭhā', i.e. sustained honest devotional paths, were prescribed by Me previously. The Yōga of knowledge for Sānkhyas, those who are predominantly knowledge oriented, and the Yōga of action for Yōgis, those who are predominantly action oriented.

Gīta Bhāshya 3.03

'sāṅkhyānāṁ' - those in pursuit of knowledge, like monk Sanaka. 'yōginām' - those who are employing action, like king Janaka. 'niṣṭhā' - state of one's existence. The right to action is determined by the will of the lord.

Even though the intellectual pursuit is superior, based on your role, action only is prescribed. Thus the lord said 'lōkē' verse with the intention to employ Arjuna in the war.

Two types of people exist. Householders like king Janaka and those who have abandoned duties like monk Sanaka, that are devoted only to knowledge. They both are devoted to knowledge only, performing duties as advocated by Me - is the purport.

'sāṅkhyānāṁ' refers to those in pursuit of knowledge, like monk Sanaka. 'yōginām' refers to those who are employing strategy like king Janaka. Even though they are devoted to knowledge, due to the eligibility arising out of the role, as per the will of the lord, they become Yōgis and support the world through Yōga of action. 'niṣṭhā' refers to the state of one's existence.

Therefore, by performing your rightful actions, you become eligible for knowledge like King Janaka, not by abandoning them like monk Sanaka, is the purport.

Certainly there are kings like Priyavrata and others, who attained knowledge performing actions as per the will of the lord. Therefore, it is said "right to action invested by the will of the lord".

Gīta Tātparya 3.03

'sāṅkhya' - Yōga that is predominantly knowledge oriented. 'yōga' - Yōga that is predominantly action oriented. 'niṣṭhā' is the determining factor for liberation.

The Yōga that is abundant in knowledge is Yōga of knowledge. The one which is abundant in action is the other.

"The Dēvas and the monks who are predominantly knowledge oriented and are called Sānkhyas. Within them, as Dēvas rely predominantly on knowledge alone, they are called "Primary-Sānkyas". Even though they are engaged in performing several actions involving miseries, they are to be understood as "Primary-Sānkyas" (mukhya-sānkyah). Others are Yōgis of action. Even the knowledgeable, when predominantly action oriented, become Yōgis of action. Certainly without these two (i.e. action and knowledge), no man attains the desirable human goals (purushartha). Perhaps, it is not possible for anyone to stay without action even for a moment. Action without knowledge cannot give the cherished human goals."

-thus states Brahmavaivarta

'niṣṭhā', i.e sustained honest devotion, is the determining factor for liberation.