S. R. Faruqi:

Mir has composed this theme at a much lower level in the third divan [{1059,5}]:

vuh ;haqiiqat ek hai saarii nahii;N hai sab me;N to
aab saa har rang me;N yih aur kuchh shaamil hai kyaa

[that whole reality is one; if it's not in everything, then
in every color, like water/luster, is it something else that's blended?]

In the second divan, he has expressed another aspect of this theme with uncommon beauty and power:

{904,10}.

This verse will be discussed in its place.

For the moment, let's look at the present verse. The presence of God Most High in everything, everywhere-- for this theme, the metaphor of 'watery color' [aabii rang] is extremely superb. 'Watery color' is used to describe a very light color-- the kind of color which, if it is mixed into some other color, apparently doesn't cause any change. An extremely light blue color is also called 'watery'. But since water is the foundation of life, in the metaphor of 'watery color' there's an allusion to life.

The use of nairang in contrast with be-rang is very fine. For nairang is used in the sense of 'enchantment' (that is, 'an amazing thing'), and also in the sense of 'a multiplicity of color'. In the Sufis' terminology, be-rangii is a quality of oneness. The Sufis have often spoken about the colorfulness of multiplicity [ka;srat] and the 'colorlessness' of oneness.

Thus Maulana-e Rum, in the 'Masnavi' (first daftar, second part) says [in Persian]:

'From two hundred colors the road is toward colorlessness.
Color is like a cloud, and colorlessness is the moon.
Whatever radiance and glitter you see within a cloud,
Consider it to be because of the stars and the moon and the sun.'

That is, when the colorlessness of God the Most High comes into the range of the senses, then it adopts different kinds of colors. The way in a cloud various kinds of colors are seen, but they are caused by the radiance of the stars or sun or moon behind the cloud-- in the same way the colorfulness of the physical world is caused by its reflection of the Divine Reality. That reality itself can't be seen, but like the moon hidden in a cloud, it makes every object colorful.

In the merging into every color like water, there's also the point that no matter what color it might be, without water it cannot be stable. Even a dry color is first made with water, then after drying out most of its water they give it the form of powder or some other form. Thus it's the marvel/enchantment of the Divine Reality that he/it is colorless like water and is also, like water, the basis of every color.

There's also the point that if water is added to color, then the color becomes light. The Divine Reality, like water, has penetrated into every color; in this way the grossness/impurity of colors (that is, entities) has been lessened.

FWP:

SETS
MOTIFS == [BELOVED IS GOD]; ISLAMIC
NAMES
TERMS

Really, the word- and meaning-play with be-rang , nairang, rang -- in a fourteen-word verse, how much better could it get?

And since rang can also refer to all sorts of 'styles' and 'aspects' less literal than 'color', we have cause to remember that aab too means not just 'water' but also 'luster, glitter, elegance', etc. (see the definitions above). It might seem that even for 'color' itself, the sense of 'luster' could work; but since colors sometimes are pale and have no luster, the claim of being within 'every color' couldn't work.

SRF brings out the Sufistic reading, and it's certainly the primary one. But the meanings of nairang that have to do with 'trickery, deceit, sorcery, pretence' also work perfectly in the context of the verse. 'Just look at how the magician plays such tricks, how he vanishes, how he reappears somewhere else!' We know he does it to entertain us, but in this beguilement might there not be sinister possibilities as well?