1148
Śrīmad-Bhāgavatam
[Canto 3, Ch. 27]
He is the support of the material cause and He enters into everything. He is absolute, one without a second, and He is the eyes of the illusory energy.
PURPORT
A pure devotee can see the presence of the Supreme Personality of Godhead in everything materially manifested. He is present there only as a reflection, but a pure devotee can realize that in the darkness of material illusion the only light is the Supreme Lord, who is its support. It is confirmed in  Bhagavad-gītā  that the background of the material manifestation is Lord Kṛṣṇa. And, as confirmed in the  Brahma-saṁhitā , Kṛṣṇa is the cause of all causes. In the  Brahma-saṁhitā  it is stated that the Supreme Lord, by His partial or plenary expansion, is present not only within this universe and each and every universe, but in every atom, although He is one without a second. The word  advayam , “without a second,” which is used in this verse, indicates that although the Supreme Personality of Godhead is represented in everything, including the atoms, He is not divided. His presence in everything is explained in the next verse.
TEXT 12
यथा जलस्य आभासः स्थलस्थेनावदृश्यते ।
स्वाभासेन तथा द्वयो जलस्थेन दिवि स्थितः ॥१२॥
yathā jala-stha ābhāsaḥ sthala-sthenāvadṛśyate svābhāsena tathā sūryo jala-sthena divi sthitaḥ
yathā—as; jala-sthaḥ—situated on water; ābhāsaḥ—a reflection; sthala-sthena—situated on the wall; avadṛśyate—is perceived; sva-ābhāsena—by its reflection; tathā—in that way; sūryaḥ—the sun; jala-sthena—situated on the water; divi—in the sky; sthitaḥ—situated.
TRANSLATION
The presence of the Supreme Lord can be realized just as the sun is realized first as a reflection on water, and again as a second reflection on the wall of a room, although the sun itself is situated in the sky.