We don’t have to dive deep into Advaita to come across the imagery of a drop of water and the ocean or many rivers flowing back to the sea. Whilst it is more prominent now, we find the same idea in classic literature,

Just as flowing rivers go down into the sea,
Leaving name and form behind,
The one who knows, freed from name and form,
Reaches the highest Supreme Self.
— Mundaka Upanishad [1]

The meaning is clear — the rivers are likened to name and form and the sea to the Supreme Self. When Advaita is realised, there is the vanishing of name and form, which is the rivers flowing back to the sea. This is very common imagery for illustrating the truth. What we may not know is that it also features in the Vedas.

The word translated as “sea” or “ocean” is samudra. In the context of Mundaka Upanishad, it represents the ‘ocean’ of consciousness or Brahman, and is so-called for its expansiveness just like a real ocean. In the Vedas, there are numerous mantras where water or multiple rivers are flowing. If we understand what causes the appearance of name and form, then we know what these rivers are referring to, as the rivers returning to the sea is having knowledge.

When rivers are mentioned in the Vedas, they tend to be seven in number. There are also seven rishis, seven horses and seven rays, amongst other things. The Brihadaranyaka Upanishad [2] explains that the seven rishis are the seven pranas and Shankara clarifies that these seven are the eyes, ears, nostrils and tongue [3].

This links back to rivers signifying name and form, as it is the interaction between the senses and their objects which is responsible for perceiving separation between oneself and Brahman. Shankara explains that the senses are obstacles because they turn one’s “vision from the Self to the sense-objects” [4]. When the senses are not restrained, one is subjected to Samsara [5]. In contrast, their restraint is the means of being liberated from Maya.

This restraint is the gateway to the pranas going to their source, which is samudra or the Self, the source of all. As horses, these pranas are described as returning to their stable [6]. With sense-restraint, the rivers flowing back to the sea, there is the disappearance of name and form (as separate from Brahman) and one sees there is no duality.

[1] 3.2.8
[2] 2.2.3
[3] Shankara’s Bhashya Brihadaranyaka Upanishad 2.2.3
[4] Shankara’s Bhashya Brihadaranyaka Upanishad 2.2.1
[5] Katha Upanishad 3.7
[6] Brihadaranyaka Upanishad 1.1.2