Srila Sukadeva Gosvami explains that Narada Muni perfectly instructed King Priyavrata about the mission of human life. The mission of human life is to realize one’s self and then gradually to go back home, back to Godhead. Since Narada Muni instructed the King fully on this subject, why did he again enter household life, which is the main cause of material bondage? Maharaja Pariksit was greatly astonished that King Priyavrata remained in household life, especially since he was not only a self-realized soul but also a first-class devotee of the Lord. A devotee actually has no attraction for household life, but surprisingly, King Priyavrata enjoyed household life very much. One may argue, “Why is it wrong to enjoy household life?” The reply is that in household life one becomes bound by the results of fruitive activities. The essence of household life is sense enjoyment, and as long as one engrosses his mind in working hard for sense enjoyment, one becomes bound by the reactions of fruitive activities. This ignorance of self-realization is the greatest defeat in human life. The human form of life is especially meant for getting out of the bondage of fruitive activities, but as long as one is forgetful of his life’s mission and acts like an ordinary animal–eating, sleeping, mating and defending–he must continue his conditioned life of material existence. Such a life is called svarupa-vismrti, forgetfulness of one’s real constitutional position. Therefore in Vedic civilization, one is trained in the very beginning of life as a brahmacari. A brahmacari must execute austerities and refrain from sex indulgence. Therefore if one is completely trained in the principles of brahmacarya, he generally does not enter household life. He is then called a naisthika-brahmacari, which indicates total celibacy. King Pariksit was thus astonished that the great King Priyavrata, although trained in the principles of naisthika-brahmacarya, entered household life.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Fifth Canto, Chapter 01 – Text 01