SB 6.11.14
sri-vrtra uvaca
distya bhavan me samavasthito ripur
yo brahma-ha guru-ha bhratr-ha ca
distyanrno ’dyaham asattama tvaya
mac-chula-nirbhinna-drsad-dhrdacirat
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Sri Vrtrasura said: He who has killed a brahmana, he who has killed his spiritual master — indeed, he who has killed my brother — is now, by good fortune, standing before me face to face as my enemy. O most abominable one, when I pierce your stonelike heart with my trident, I shall be freed from my debt to my brother.