FWP:
SETS == A,B; IZAFAT
All the commentators I've looked at say more or less the above. This perplexed me. Why would we be worrying about how hot the nighttime lament was, or which way it entered and left the heart? No doubt the lament can damage the heart with its fieriness, but that's just in the nature of things-- why would we bother about hunting it down the next day? By then, there's no 'it' to hunt down, anyway. A lament doesn't seem like a good analogy to a thief or other night-prowler.
Then I realized that this is one of those 'A,B' verses: it's up to us to decide the relationship between the lines, since Ghalib has left us no 'trace' to tell us how to do so. The commentators decided that both lines were parallel and referred to exactly the same situation, so they spent their time explaining which of the four entities in the first line corresponded to the 'footprint', and which to the 'night-prowler'. I'm not convinced that this is the most interesting reading. For it's equally possible that the two lines are meant to be linked more loosely, and the sneaky multivalence of the i.zaafat constructions must be allowed for.
So I have another and quite different reading to propose. In a common mushairah-verse style, the first line is incomprehensible without the second. When we finally are allowed to hear the second line, only then do we realize that we are probably searching for traces of a villain, a marauder, a dangerous intruder of some kind who is now long gone; we deduce this, since the second line seems to illustrate or justify a similar procedure.
But the intruder, the 'thief in the night', is not necessarily present in the first line. The ambiguities of the i.zaafat constructions can easily allow for this absence. 'Trace of the steam/heat of the lament' can just as easily mean 'trace which consists of...' (my reading) as it can 'trace left by...' (the commentators' reading).
Everything in the first line is, on my reading, an elaborate description of the scene of the crime-- the trail of damage wrought by the marauder. Thus the lament, with its hot and steaming residue, is not a villain but a sign of victimization; like the wound in the heart, it is a casualty left behind by the marauder's passing through. That's why we need to cleverly find the track of the marauder by following his trail: all we can use to track him is 'the trace of the steam of the lament, from the wound of the heart'. This careful scene-of-the-crime work is comparable to the way people track the footprints of a (real, physical) night-prowler.
And who is the night-prowler, the robber, the marauder? We
know already. It's the beloved, of course, sneaking around and penetrating
the lover's heart, damaging it irreparably, shooting her glance-arrows from
afar. We already know that she comes to the lover in dreams-- consider how
cruel she is to her dream-tormented lover in {10,10}
and {97,3}.
Nazm:
The time for lamentation is always night. This is why he's called the lament a night-prowler. He says, the way in the morning they see the night-prowler's footprint and pick up his track-- he came from this side, and went from that side-- in the same way the track of the heat and warmth of the nighttime lament cam be picked up. (98)
== Nazm page 98