S. R. Faruqi:

In the first line the pleasure is that the fear because of which he has restrained the tears from falling-- he hasn't expressed the reason for it. It's possible that it might be fear of the beloved, it's possible that it might be fear of the people of the world (that is, of the Advisors, of the taunters and abusers), it's possible that it might be fear of the beloved's disgrace, it's possible that it might be fear of his own disgrace, it's possible that it might be fear of the tears, since they're falling for the first time-- he's never even seen tears fall, the Lord knows what disaster this might evoke! Because he has kept the reason ambiguous, a perfect eloquence [balaa;Gat] has been created in the line.

In the second line, how beautiful is the opposition of tears with fire! If he had wept, then perhaps some peace would have come to his heart; when he restrained his tears, then the restlessness further increased, to such an extent that it seemed as if fire was spreading throughout his body. Ghalib's verse has certainly been borrowed from Mir:

G{6,6}.

But in Ghalib's verse the 'commonality' [muraa((at ul-na:ziir], and in the second line the ambiguity of niklaa , are very fine. In addition, Ghalib has made no direct mention of of the drinking of tears, but rather has made so eloquent an allusion to the whole event that the story makes itself understood of its own accord.

Mir's verse has one kind of excellence like that of Ghalib's: that he has construed the drop of water as an agent in its own right (the drop of water has lit a fire in our body and passed on). In Ghalib's verse, that drop becomes a typhoon; that is, it acts on its own behalf. In terms of both astonishment and sorrow, the effect is very fine. By using the word phir , Ghalib has alluded to a continuing action. Mir's verse is devoid of this excellence. By contrast, to drink tears out of fear, and to keep them hidden out of fear itself, is an excellence of Mir's verse that is not in Ghalib's.

Mir has expressed his theme at a very low level in the first divan [{449,7}]:

jo aa;Nsuu pii gayaa mai;N aa;xir ko miir un ne
chhaatii jalaa jigar me;N ik aag jaa lagaa))ii

[those tears that I drank-- finally, Mir, they
having burned the breast, went and lit a single/particular/unique/excellent flame in the liver]

In Persian, he has changed the theme a bit and composed it like this:

'The heart, that in my breast was a drop of blood,
When it came to the eyes, then I saw in it the style of a typhoon.'

This theme he had already composed with great excellence in Urdu, in the first divan [{6,4}]:

jigar hii me;N ik qa:trah ;xuu;N hai sirishk
palak tak gayaa to talaa:tum kiyaa

[only/emphatically in the liver is a tear a single/particular/unique/excellent drop of blood
when it went as far as the eyelashes then it created a wave-buffeting]

But the theme of drinking tears because of fear belongs in reality to Ni'mat Khan Ali [in Persian]:

'It became the tumult of Doomsday and rose up from that side of the world,
The lament that I had hidden through fear of you.'

In Mir's verse the mood of shame is greater. Ghalib's mood is close to Ni'mat Khan Ali's. But Mir's verse, through the situation of personal expression, makes more claim on the attention.

FWP:

SETS == EK
MOTIFS
NAMES
TERMS == AMBIGUITY; IZAFAT; THEME; WORDPLAY

The verse depicts a spectacular progression: The generalized 'tears' become epitomized as 'that drop of water'. Then the restrained tear-drop (in English, similarly, people can be said to 'swallow' their tears), taken back into the body, somehow autonomously kindles in the body a single and/or special [ek] kind of fire. And having done so, the fire seems to take its leave, heading for parts unknown. The casual compression of lagaa gayaa adds to the effect: the teardrop-firespark, having in passing, offhandedly, started a conflagration, then mysteriously rides off into the sunset (if it can turn from water to fire, I don't see why it can't then leave town on horseback).

Vatsal Sharma suggests (Feb. 2021) that people might enjoy hearing SRF discuss this verse in the course of a talk he gave at the University of Chicago in 1990.

Note for grammar fans: Transitive verbs, when compounded, normally take transitive auxiliaries; exceptions in which they take intransitive auxiliaries like jaanaa are almost always idiomatic expressions with special meanings. In the first line we see such an exception: the idiom pii jaanaa , 'to drink up', is parallel to khaa jaanaa , 'to eat up, to consume entirely'. In the second line, lagaa gayaa looks like a case of kar deletion: having kindled/'attached' a fire, the teardrop 'went'/departed. I enjoyed taking this 'official' reading literally, but lagaa gayaa can also be used casually and idiomatically as though it basically meant lagaayaa ; this is how SRF seems to take it. Compound verbs are one of the great creative 'growing points' for idiomatic usages in Urdu, and they're often remarkably hard to pin down. (Think of how creatively we use 'get' in English: get away with it, get on with it, get by with it, get around it, get out of it, get into it, get through it, get over it, get it on, etc.). For more on this see {1781,1}.

Another note for grammar fans: The meter makes it clear that qa:trah aab can't have an i.zaafat . So the two nouns have to just sit there, bonded into a compound in a way that's more natural to Persian than to Urdu. It could be considered to be an 'omitted izafat', if we choose. But note that colloquial usage can also admit ik buu;Nd paanii , which would have to be taken just as an idiomatic way of expressing an amount; so the same option is available here too.