Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 40

Sanskrit:

कृत्यानल: प्रतिहत: स रथाङ्गपाणे-रस्त्रौजसा स नृप भग्नमुखो निवृत्त: ।वाराणसीं परिसमेत्य सुदक्षिणं तंसर्त्विग्जनं समदहत् स्वकृतोऽभिचार: ॥ ४० ॥

ITRANS:

kṛtyānalaḥ pratihataḥ sa rathānga-pāṇerastraujasā sa nṛpa bhagna-mukho nivṛttaḥvārāṇasīṁ parisametya sudakṣiṇaṁ taṁsartvig-janaṁ samadahat sva-kṛto ’bhicāraḥ

Translation:

Frustrated by the power of Lord Kṛṣṇa’s weapon, O King, the fiery creature produced by black magic turned his face away and retreated. Created for violence, the demon then returned to Vārāṇasī, where he surrounded the city and then burned Sudakṣiṇa and his priests to death, even though Sudakṣiṇa was his creator.

Purport:

Śrīla Prabhupāda comments as follows: “Having failed to set fire to Dvārakā, the fiery demon went back to Vārāṇasī, the kingdom of Kāśirāja. As a result of his return, all the priests who had helped instruct the black art of mantras, along with their employer, Sudakṣiṇa, were burned into ashes by the glaring effulgence of the fiery demon. According to the methods of black-art mantras instructed in the tantra, if the mantra fails to kill the enemy, then, because it must kill someone, it kills the original creator. Sudakṣiṇa was the originator, and the priests assisted him; therefore all of them were burned to ashes. This is the way of the demons: the demons create something to kill God, but by the same weapon the demons themselves are killed.”