Mahabharata 13.130.49

आत्मानमुपजीवन्यो दीक्षां द्वादशवार्षिकीम्अश्मना चरणौ भित्त्वा गुह्यकेषु स मोदते

ātmānamupajīvanyo dīkṣāṃ dvādaśavārṣikīmaśmanā caraṇau bhittvā guhyakeṣu sa modate

Our plain-language meaning of this verse is waiting for scholar review.