Bhagavad Gita Chapter 9, Verse 3

अश्रद्धधानाः पुरुषा धर्मस्यास्य परन्तप | अप्राप्य मां निवर्तन्ते मृत्युसंसारवर्त्मनि ||

aśraddadhānāḥ puruṣā dharmasyāsya parantapa aprāpya māṁ nivartante mṛtyu-saṁsāra-vartmani

O Arjuna, those who have no faith in this dharma, without attaining Me, return to the path of death and repeated birth.

Krishna reveals the consequence of disregarding this royal knowledge. Those who have no faith (ashraddhadhanah) in this dharma (dharmasya asya)—this royal knowledge—without attaining (aprapya) Me (mam), return (nivartante) to the path of death and repeated birth (mrityu-samsara-vartmani). This is the folly of disregarding the Supreme: without faith, you can't attain the Supreme. Without attaining the Supreme, you remain in the cycle of birth and death. This is the consequence of not having faith in the royal knowledge—you return to samsara, the cycle of suffering. This isn't punishment—it's the natural consequence of not having faith in the highest path.