The ocean is probably Rumi's favorite image for what it is to live in the world. It requires a different kind of breathing and a different kind of movement. The water we dive into lies deeper than the land we walk upon. Here's another example of the ocean metaphor; Rumi says:

The Ocean will not allow its fish out of itself.
Nor does it let land animals in
where the subtle and delicate fish move.

The land creatures lumber along on the ground.
No cleverness can change this. There's only one
Opener for the lock of these matters.

Forget your figuring. Forget your self. Listen to your Friend.
When you become totally obedient to That One,
you'll be free.
(Longing: 35)

More Oceans here at Sunday Scribblings.