Although Prahlada Maharaja was a grhastha ruling over the demons, he was a paramahamsa, the best of human beings, and thus he is our guru. In the list of gurus, or authorities, Prahlada Maharaja's name is therefore mentioned

Expressions researched:
"although Prahlāda Mahārāja was a gṛhastha ruling over the demons, he was a paramahaṁsa, the best of human beings, and thus he is our guru. In the list of gurus, or authorities, Prahlāda Mahārāja's name is therefore mentioned"

Srimad-Bhagavatam

SB Canto 7

A guru, or spiritual master, can be anyone who is well conversant with the science of Kṛṣṇa. Therefore although Prahlāda Mahārāja was a gṛhastha ruling over the demons, he was a paramahaṁsa, the best of human beings, and thus he is our guru. In the list of gurus, or authorities, Prahlāda Mahārāja's name is therefore mentioned.

SB 7.13.46, Translation and Purport

Nārada Muni continued: After Prahlāda Mahārāja, the King of the demons, heard these instructions from the saint, he understood the occupational duties of a perfect person [paramahaṁsa]. Thus he duly worshiped the saint, took his permission and then left for his own home.

As quoted in Caitanya-caritāmṛta (CC Madhya 8.128), Śrī Caitanya Mahāprabhu said:

kibā vipra, kibā nyāsī, śūdra kene naya

yei kṛṣṇa-tattva-vettā sei 'guru' haya

A guru, or spiritual master, can be anyone who is well conversant with the science of Kṛṣṇa. Therefore although Prahlāda Mahārāja was a gṛhastha ruling over the demons, he was a paramahaṁsa, the best of human beings, and thus he is our guru. In the list of gurus, or authorities, Prahlāda Mahārāja's name is therefore mentioned:

svayambhūr nāradaḥ śambhuḥ

kumāraḥ kapilo manuḥ

prahlādo janako bhīṣmo

balir vaiyāsakir vayam

The conclusion is that a paramahaṁsa is an exalted devotee (bhagavat-priya). Such a paramahaṁsa may be in any stage of life—brahmacāri, gṛhastha, vānaprastha or sannyāsa—and be equally liberated and exalted.