B.G 3.04

न कर्मणामनारम्भान्नैष्कर्म्यं पुरुषोश्नुते। न च संन्यसनादेव सिद्धिं समधिगच्छति ॥४॥

No one attains perfection by non-commencement of work, or by inaction, nor does one attain the goal by mere renunciation.

Gīta Tātparya 3.04

Self-less action results in knowledge. Without knowledge, there can be no liberation.

"ज्ञानिनो मोक्षनियमः तथापि शुभकर्मणा। आनन्दवृद्धिरन्येन ह्रासो ज्ञानं तु कर्मणा॥"

"The Janānin will finally get liberated is the rule. Similarly, benevolent act always increase bliss, and others decrease it. The action results in knowledge."

इति परमश्रुतेः।

- states Parama Vedic testimonial.

"न कर्मणा न प्रजया धनेन" इत्यादिविरोधो न। अन्यथा "न कर्मणामनारम्भात्" इत्याद्युभय समवाक्यशेषविरोधश्च। समत्वं च "न हि कश्चित्" इत्यादेः। "नान्यः पन्थाः" इत्यपि ज्ञानमृते न मोक्ष इत्येवाह ॥३॥

Testimonials such as "not by action, not by progeny, not by wealth" are not opposed (to performing action intending to gain knowledge). Otherwise, there is opposition to the statement "Not by merely abstaining from work" which is a testimonial with equal weight. Regarding equivalent statements, there can't be contradiction, is the rule. There also exist testimonials that state "there is no other way", that indicate without knowledge there can be no liberation.

Note: Following verse is quoted:
न कर्मणा न प्रजया धनेन त्यागेनैके अमृतत्वमानशुः| परेण नाकं निहितं गुहायां विभ्राजते यद्यतयो विशन्ति॥
The self-controlled, who are of pure minds have well ascertained the Reality and state: "Higher than heaven, seated in the cave (Buddhi), that shines, (which) the self-controlled attain. Not by work, nor by progeny, nor by wealth, but only by renunciation, they attained immortality."
- Kaivalya Upanishad