Darkness can cover a small cave, but not the open sky. Similarly, the covering capacity of the material energy is limited and cannot act on the Supreme Personality of Godhead, who is therefore called vibhu
SB Canto 3
As His pastime, that Supreme Personality of Godhead, the greatest of the great, accepted the subtle material energy, which is invested with three material modes of nature and which is related with Viṣṇu.
In this verse the word guṇamayīm is very significant. Daivīm means "the energy of the Supreme Personality of Godhead," and guṇamayīm means "invested with the three modes of material nature." When the material energy of the Supreme Personality of Godhead appears, this guṇamayīm energy acts as a manifestation of the energies of the three modes; it acts as a covering. The energy emanated from the Supreme Personality of Godhead manifests in two ways—as an emanation from the Supreme Lord and as a covering of the Lord's face. In Bhagavad-gītā it is said that because the whole world is illusioned by the three modes of material nature, the common conditioned soul, being covered by such energy, cannot see the Supreme Personality of Godhead. The example of a cloud is very nicely given. All of a sudden there may appear a big cloud in the sky. This cloud is perceived in two ways. To the sun the cloud is a creation of its energy, but to the ordinary common man in the conditioned state, it is a covering to the eyes; because of the cloud, the sun cannot be seen. It is not that the sun is actually covered by the cloud; only the vision of the ordinary being is covered. Similarly, although māyā cannot cover the Supreme Lord, who is beyond māyā, the material energy covers the ordinary living entities. Those conditioned souls who are covered are individual living entities, and He from whose energy māyā is created is the Supreme Personality of Godhead.
In another place in the Śrīmad-Bhāgavatam, in the First Canto, Seventh Chapter, it is stated that Vyāsadeva, by his spiritual vision, saw the Supreme Lord and the material energy standing behind Him. This indicates that material energy cannot cover the Lord, just as darkness cannot cover the sun. Darkness can cover a jurisdiction which is very insignificant in comparison to that of the sun. Darkness can cover a small cave, but not the open sky. Similarly, the covering capacity of the material energy is limited and cannot act on the Supreme Personality of Godhead, who is therefore called vibhu. As the appearance of a cloud is accepted by the sun, so the appearance of the material energy at a certain interval is accepted by the Lord. Although His material energy is utilized to create the material world, this does not mean that He is covered by that energy. Those who are covered by the material energy are called conditioned souls. The Lord accepts the material energy for His material pastimes in creation, maintenance and dissolution. But the conditioned soul is covered; he cannot understand that beyond this material energy there is the Supreme Personality of Godhead, who is the cause of all causes, just as a less intelligent person cannot understand that beyond the covering of the clouds there is bright sunshine.