CC Madhya 15.135

‘dāru-brahma’-rūpe — sākṣāt śrī-puruṣottama
bhāgīrathī hana sākṣāt ‘jala-brahma’-sama
Word for word: 
dāru-brahma-rūpe — in the form of Brahman as wood; sākṣāt — directly; śrī-puruṣottama — Lord Jagannātha; bhāgīrathī — the river Ganges; hana — is; sākṣāt — directly; jala-brahma-sama — the Supreme in the form of water.
Translation: 
“Lord Jagannātha is the Supreme Lord Himself in the form of wood, and the river Ganges is the Supreme Lord Himself in the form of water.
Purport: 

The Vedas enjoin, sarvaṁ khalv idaṁ brahma: everything is the energy of the Supreme Personality of Godhead, the Supreme Brahman or Parambrahma. Parasya brahmaṇaḥ śaktis tathedam akhilaṁ jagat: everything is a manifestation of the energy of the Supreme Brahman. Since the energy and energetic are identical, actually everything is Kṛṣṇa, Parambrahma. In the Bhagavad-gītā (9.4) Lord Kṛṣṇa confirms this:

mayā tatam idaṁ sarvaṁjagad avyakta-mūrtinā
mat-sthāni sarva-bhūtāni
na cāhaṁ teṣv avasthitaḥ

“By Me, in My unmanifested form, this entire universe is pervaded. All beings are in Me, but I am not in them.”

Kṛṣṇa is spread throughout the whole universe in His impersonal form. Since everything is a manifestation of the Lord’s energy, the Lord can manifest Himself through any energy. In this age, the Lord is manifest through wood as Lord Jagannātha, and He is manifest through water as the river Ganges. Therefore Śrī Caitanya Mahāprabhu ordered the two brothers — Sārvabhauma Bhaṭṭācārya and Vidyā-vācaspati — to worship Lord Jagannātha and the river Ganges.