S. R. Faruqi:

In the second line, the insha'iyah style is fine; the idea too is brand-new. When the reflection of red flowers casts its shade, then it seems that the water-channels have been filled with red wine. In the first line he has said that it seems that in the water-channels there's not water but wine; then the thought comes to him-- would this not be the reflection of flowers that is making the water colorful?

But he has expressed the idea in such a way that two meanings emerge:

(1) In a tone of prayer/blessing-- oh God, in these water-channels may the water never be devoid of the reflection of flowers. That is, may the spring remain enduring and established, and beside the water-channels may the swaying flowers keep casting their reflection into the water, so that the water-channels may always wear the guise of being full of wine.

(2) In a tone of distrust and hopelessness he has said, Oh God, may it not be that there would be no wine in the water-channels, but rather water! -- and when the reflection of rose and tulip would move away from the water, then it would be clear that this colorfulness was the reflection of red flowers, not of wine.

The unchecked flight of the imagination is so devastating that we can call it only a kind of madness. An ordinary man cannot fall into such an error, and then come to doubt it in such a way. He has composed this theme in other places as well, but in the present verse the abundance of meaning has created a poetic power.

From the first divan [{572,5}] (where taklīf means 'to tell someone to bring something'):

kyūñ-kih be-bādah lab-e jū pah chaman meñ rahiye
ʿaks-e gul āb meñ taklīf-e mai-e gul-gūñ hai

[why/how, without wine, would one remain at the edge of the stream, in the garden?
the reflection of the rose in the water is a request for rose-colored wine]

From the sāqī-nāmah :

thā ġhairat-e bādah ʿaks-e gul se
jis jū-e chaman se āb niklā

[it was the envy of wine, from the reflection of the rose--
the stream in the garden from which water emerged]

[See also {1354,3}.]

FWP:

SETS
MOTIFS == WINE
NAMES == GOD
TERMS == INSHA'IYAH

Those final few words in the second line, āb nah ho , are really nothing more than the rhyming elements; but in context, they are also perfectly constructed for permutations (see the definition of āb above). Here's how some of the possibilities would go:

'Without the reflection of rose and tulip, oh God! in those streams,

may there not be
there would not be
there might not be

water
radiance
honor'

By the time we've rung all the changes on the grammar and the insha'iyah tone, we've got anything from a blessing to a curse, anything from an endorsement of perpetually rose-colored water to a claim that without the color of the rose and tulip there might (or would, or should) be no water (or radiance, or honor) at all.

The reflections of the rose and tulip have not really filled the water-channels with wine, but have only 'so to speak' done so (see the definition above). The speaker doesn't at all think the wine is actual; what he is praising is the brilliiant ruby-red reflection of the rose and tulip in the water. That seems quite proper, for in the lover's world, doesn't all radiance, along with all intoxication, come from the glory of the rose?