FWP:
SETS == KIH; MIDPOINTS; PARALLELISM
On the idiomatic grammar of nah bane expressions, see {191,8}.
The two lines are parallel, but with intriguing differences. The action proposed in the first line is something like 'looking out for', death [maut kii raah dekhnaa], literally, to 'watch the road' by which it's expected to come. So it suggests an eagerness and attention and desire that are stronger than merely passively 'to await'. But neither is it the same as chaahnaa , to 'desire' or 'love', in the second line. Are we to pay attention to the similarities, or the differences? Both, no doubt, since this is Ghalib.
Moreover, nothing in the grammar rules out doing both activities at once. Nor does anything in the grammar establish any other relationship between the lines: the idea that death is a new beloved who might supplant the old one; or the alternative idea that waiting for death is a mere counsel of despair because of the beloved's inaccessibility; or Bekhud Mohani's notion that the man of courage should love the beloved actually because of her inaccessibility-- these and other such interpretations can be present only by implication, since the verse itself doesn't formally produce them.
There's also the elegant multivalence of kih -- 'since, because'? 'for'? 'in that'? 'such that'? 'the one which/who'? The particular (causal or non-causal) relationship between the clause before it and the clause that it introduces is always open to mediation by each semantic situation in which it occurs. For an excellent example of such flexibility, just compare the use of kih in the next verse, {191,8}, where it clearly means something like 'the one that'.
Ghalib in his letter seems to pride himself on a kind of iihaam (in an extended sense) that he's created by careful arrangement of the 'midpoints' grammar of the second line. As he explains it, in the first reading (or, ideally, hearing), we naturally take the first two clauses together, because of the apparent parallelism with the first line, so that the 'midpoint' phrase kih nah aa))o is read with the first part of the line ('should I desire you, because you might not come?'); only after hearing the final clause do we go back and-- enjoyably, on the fly-- revise our initial guess (to read kih nah aa))o with the latter part of the line).
Note for grammar fans: This radically inshaa))iyah verse is a kind of textbook of the future subjunctive-- no fewer than five instances occur. Along with two idiomatically-used past participles, they are the only verbs in the verse. Their flexibility is cleverly exploited: the first subjunctive in each line is a proposed action that the speaker is seriously considering, so that in English it would have the sense more or less of 'should I...?'. By contrast, the other subjunctives all simply describe, in the classic subjunctive way, actions might or might not happen. This former, deliberative sense is available only in the first person, because one can't deliberate about, or choose, other parties' actions. The subjunctive can of course also express a wish or hope, as in {173,6}.
Compare {201,2}, which meditates on the capriciousness of death.
Ghalib:
[1853, to Haqir:] Brother, I am greatly surprised at you, that you felt a hesitation about the meaning of this verse [bait]. Two questions have come into it that he has asked of the beloved by way of reproach and insinuation. Should I not wait for death? Why should I not? I will indeed wait for it, for it can't not come. For this is one of the things thing to the honor [shaan] of death, that one day it will indeed come. The wait will not be in vain. Should I desire you? What a fine idea! Why should I desire you, when if you don't come, you can't be called? That is, if you would come of your own will, then you'd come, and if you wouldn't come, then what power would anyone have to call you?
As if this helpless one says to the beloved, 'Now I've left you and have become a lover of death. It has the virtue that without being called, it doesn't refrain from coming. Why would I desire you, when if you don't come, then I can't call you?' The thing is that if in reading 'should I desire you, since you wouldn't come' [tum ko chaahuu;N kih nah aa))o] this utterance comes into the mind joined together, then a person is amazed [;hairaan]. tum ko chaahuu;N is separate, kih nah aa))o to bulaa))e nah bane -- this phrase is separate. You didn't pay attention, otherwise the mood of this reproach and insinuation would of itself have become apparent to you.
==Urdu text: Khaliq Anjum vol. 3, p. 1117