avyaktāya ca devānāṁ
devāya sva-puraṁ yayau
The Supreme Lord is not visible to material eyes, but when the material senses are inclined to the transcendental loving service of the Lord and are thus purified, the Lord reveals Himself to the vision of the devotee. Avyakta means “unmanifested.” Although the material world is the creation of the Supreme Personality of Godhead, He is unmanifested to material eyes. Mahārāja Pṛthu, however, developed spiritual eyes by his pure devotional service. Here, therefore, the Lord is described as sandarśitātmā, for He reveals Himself to the vision of the devotee, although He is not visible to ordinary eyes.
Thus end the Bhaktivedanta purports of the Fourth Canto, Twentieth Chapter, of the Śrīmad-Bhāgavatam, entitled “Lord Viṣṇu’s Appearance in the Sacrificial Arena of Mahārāja Pṛthu.”