SB 7.10.35
evam ca parsadau visnoh
putratvam prapitau diteh
hrdi sthitena harina
vaira-bhavena tau hatau
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Thus the two associates of Lord Visnu who had become Hiranyaksa and Hiranyakasipu, the sons of Diti, were both killed. By illusion they had thought that the Supreme Lord, who is situated in everyone’s heart, was their enemy.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The discourse concerning Lord Nrsimhadeva and Prahlada Maharaja began when Maharaja Yudhisthira asked Narada how Sisupala had merged into the body of Krsna. Sisupala and Dantavakra were the same Hiranyaksa and Hiranyakasipu. Here Narada Muni is relating how in three different births the associates of Lord Visnu were killed by Lord Visnu Himself. First they were the demons Hiranyaksa and Hiranyakasipu.