S. R. Faruqi:

se = like

Fragments of the liver that emerge and flow along with tears and have fallen on the garment-hem-- to call them 'sparks' is an eloquent [badii((] thing. A more eloquent thing is that for fragments of the liver to come and fall on the garment-hem is as if, so to speak, someone would have filled the lap with fire. Having spread out the garment-hem [to form a skirt that can hold things], people ask for alms or gifts. In the garment-hem they accumulate valuable things and take them away, if the amount is great and there's no other means of carrying them.

Here, by using the theme of filling up the lap or garment-hem with sparks, he has created an extraordinary 'mood'. As if those sparks are for one or another reason are precious, or are valuable. And although it's not clear to the speaker why they are valuable, in an unconscious way he's aware that they are valuable-- thus he speaks of his 'lap' being filled. He doesn't say that his garment-hem is burning (as in

{15,1},

and

{15,3});

rather, he says that his lap has been filled with fire.

In the whole verse is an atmosphere of melancholy; but there's no self-pity, nor is there any humility and painfulness. There's a kind of amazement and sorrowful surprise. Here too there's no abundance of meaning. But because the images are eloquent, the deficiency of meaning is not felt.

FWP:

SETS
MOTIFS == LIVER
NAMES
TERMS == IMPLICATION; MOOD

On this kind of colloquial use of nah , see {52,2}. SRF seems to find the usage so natural that he doesn't even mention it.

One time period was 'formerly' [aage], an era when burning liver-fragments used to fall into the speaker's lap from time to time [jab tab]. By contrast, 'now' is a later time when the speaker's lap is full of fire.

This emphasis on time periods also adds to the pleasure of jab tab , which of course means 'from time to time, occasionally ' (see the definition above) but literally means 'when then'. Since we already basically have aage versus ab , having 'when then' in the middle gives the whole complex construct an extra fillip of pleasure.

Clearly the speaker has been sitting in the same position for a long time, with his head lowered, weeping liver-bloody, fiery tears into his own lap and thus capturing the occasional spark. This lover-like behavior is of course highly commendable. Equally admirable is his gradually accumulating a whole lapful of fire, which apparently doesn't burn him or itself become extinguished. Doesn't this suggest that his whole essence is now fiery, or at least hospitable to fire?