SB 7.10.42
esa brahmanya-devasya
krsnasya ca mahatmanah
avatara-katha punya
vadho yatradi-daityayoh
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In this narration about Krsna, the Supreme Personality of Godhead, various expansions or incarnations of the Lord have been described, and the killing of the two demons Hiranyaksa and Hiranyakasipu has also been described.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Avataras, or incarnations, are expansions of the Supreme Personality of Godhead — Krsna, Govinda.
advaitam acyutam anadim ananta-rupam
adyam purana-purusam nava-yauvanam ca
vedesu durlabham adurlabham atma-bhaktau
govindam adi-purusam tam aham bhajami
“I worship the Supreme Personality of Godhead, Govinda, who is the original person — nondual, infallible, and without beginning. Although He expands into unlimited forms, He is still the original, and although He is the oldest person, He always appears as a fresh youth. Such eternal, blissful and all-knowing forms of the Lord cannot be understood by the academic wisdom of the Vedas, but they are always manifest to pure, unalloyed devotees.” (Brahma-samhita 5.33) The Brahma-samhita describes the avataras. Indeed, all the avataras are described in the authentic scriptures. No one can become an avatara, or incarnation, although this has become fashionable in the Age of Kali. The avataras are described in the authentic scriptures (sastras), and therefore before one risks accepting a pretender as an avatara, one should refer to the sastras. The sastras say everywhere that Krsna is the original Personality of Godhead and that He has innumerable avataras, or incarnations. Elsewhere in the Brahma-samhita it is said, ramadi-murtisu kala-niyamena tisthan: Rama, Nrsimha, Varaha and many others are consecutive expansions of the Supreme Personality of Godhead. After Krsna comes Balarama, after Balarama is Sankarsana, then Aniruddha, Pradyumna, Narayana and then the purusa-avataras — Maha-Visnu, Garbhodakasayi Visnu and Ksirodakasayi Visnu. All of them are avataras.
One must hear about the avataras. Narrations about such avataras are called avatara-katha, the narrations of Krsna’s expansions. Hearing and chanting these narrations is completely pious. Srnvatam sva-kathah krsnah punya-sravana-kirtanah. One who hears and chants can become punya, purified of material contamination.
Whenever there are references to the avataras, religious principles are established, and demons who are against Krsna are killed. The Krsna consciousness movement is spreading all over the world with two aims — to establish Krsna as the Supreme Personality of Godhead and to kill all the pretenders who falsely present themselves as avataras. The preachers of the Krsna consciousness movement must carry this conviction very carefully within their hearts and kill the demons who in many tactful ways vilify the Supreme Personality of Godhead, Krsna. If we take shelter of Nrsimhadeva and Prahlada Maharaja, it will be easier to kill the demons who are against Krsna and to thus reestablish Krsna’s supremacy. Krsnas tu bhagavan svayam: Krsna is the Supreme Lord, the original Lord. Prahlada Maharaja is our guru, and Krsna is our worshipable God. As advised by Sri Caitanya Mahaprabhu, guru-krsna-prasade paya bhakti-lata-bija. If we can be successful in getting the mercy of Prahlada Maharaja and also that of Nrsimhadeva, then our Krsna consciousness movement will be extremely successful.
The demon Hiranyakasipu had so many ways to try to become God himself, but although Prahlada Maharaja was chastised and threatened in many ways, he rigidly refused to accept his powerful demoniac father as God. Following in the footsteps of Prahlada Maharaja, we should reject all the rascals who pretend to be God. We must accept Krsna and His incarnations, and no one else.