Verse 4.42

तस्मादज्ञानसंभूतं हृत्स्थं ज्ञानासिनाऽऽत्मनः। छित्त्वैनं संशयं योगमातिष्ठोत्तिष्ठ भारत।।4.42।।

tasmād ajñāna-sambhūtaṁ hṛit-sthaṁ jñānāsinātmanaḥ chhittvainaṁ sanśhayaṁ yogam ātiṣhṭhottiṣhṭha bhārata

Meaning

So, yo, use the sword of self-knowledge to slay that ignorance-fueled self-doubt in your heart. Embrace Yoga. Get your a** up, Arjuna!

Commentary

Bro, doubt is a total mindf***. It's, like, the most wicked sh*t ever. It's born from being clueless AF. So, obliterate that sh*t with self-knowledge. Now get up and fight, Arjuna!