Brahmandapurana 3.43.62

Brahmāṇḍapurāṇa 3.43.62

guruṃ huṅkṛtya tuṅkṛtya vipraṃ vādairvijitya ca /
vikāsya guhyaśāstrāṇi bhavanti brahmarākṣasāḥ //