S. R. Faruqi:

The wordplay of ka;Tii and te;G is fine. Then if the lament was, for the life, doing the work of a sword, then the meaning appears that with every lament the thread of life too was slightly, slightly, being cut. The meaning of the night's passing is in itself that the night of the lifetime was passed/'cut'. But since the lament was doing the work of a 'drawn sword', so with every sigh the lifetime too was being passed/'cut'. If the speaker had not lamented, then perhaps his lifetime would have been somewhat longer. In this there's realistic depiction too, because excessive lamentation is usually harmful to one's life.

Through his not making clear who is the addressee of 'don't ask', the pleasure is that it's possible that he might be talking with the beloved herself. In this case, an aspect emerges that the beloved has met with him at the time when because of his sighing his life has so much diminished that now very little time remains for him to enjoy the pleasure of the beloved's company. The wordplay of naalah and kashiidah is also interesting. Because [in Persian] they use kashiidan as a verb for 'to draw/heave a sigh'.

FWP:

SETS == INEXPRESSIBILITY; WORDPLAY
MOTIFS == SWORD
NAMES
TERMS == WORDPLAY

This is a verse with superb wordplay. There's basically nothing else going on in it-- but then, does there need to be? Surely the interactive pleasures of ka;Tnaa and (above all) kashiidah provide ample relish, since the whole show is generated by merely two lines and seventeen words.

In the ghazal world, the 'night of separation' is notoriously endless. How can its infinite length ever be passed, or literally, 'cut'? Why, by a metaphorical 'sword', of course. The sword is 'drawn' [kashiidah] in the sense of having been pulled out of its scabbard, ready for action, so that it can be used to 'cut' the night. And most enjoyably to wordplay fans, a 'drawn' sword is also 'drawn out' in the sense of being 'lengthened, prolonged'-- and the metaphorical process is so intuitive and immediate that we can capture many of the same senses in English idiomatic usage as well. Moreover, the lament-sword is also 'drawn' in the related Urdu idiomatic senses of being 'endured, suffered', or being 'disturbed, vexed' (see the definition above). Needless to say, all those senses too are relevant to the situation of the lover in the verse.

Finally, there's the connection between the lament-sword's cutting-through of the night of separation, and its simultaneous cutting-through of the lover's life. Because the night of separation can only end when the lover's life ends? Because the cutting power of the laments 'takes a lot out' of the lover in a very literal sense? Because now that the lover's life is over, there's no one left who can explain what happened ('don't ask')?