sar-rishtah-e be-taabii-e dil dar girih-e ((ajz
parvaaz bah ;xuu;N ;xuftah-o-faryaad rasaa hai
1) the thread of the agitation of the heart-- through the knot/entanglement of weakness
2) flight is with 'sleeping blood', and complaint is successful/'arriving'
sar-rishtah : 'End of a cord or thread, &c.; rope, cord, thread, line; series; connexion, affinity; rule, practice, course, custom, usage, form; rites, ceremonies'. (Platts p.653)
be-taabii : 'Faintness; agitation, restlessness, uneasiness, impatience; lack of splendour or lustre'. (Platts p.204)
girih : 'A knot; knob; node; ... (fig.) an entanglement, a difficulty; impediment (in speech); prejudice; misunderstanding, dissension'. (Platts p.906)
rasaa : 'Arriving, attaining; causing to arrive (used as last member of compounds); quick of apprehension, acute, sharp, penetrating, skilful, capable, clever; — mixing or mingling (with); amiable; well-received, welcome'. (Platts p.591)
;xuun ;xuftah or ;xuftan-e ;xuun = for someone's blood to be shed that would be licit [bi;hil], for which there would be no accountability. A bird has been captured. There is a plan to slaughter him. His heart is agitated, but in the thread of that agitation the knot of weakness has occurred-- that is, the repairing of the agitation of the heart cannot take place. The blood/slaughter of a prey animal is licit. Its flight is lost in that expected slaughter that will not be avenged, but its complaint is very high-flying. That is, the prey can take no action; it is strongly lamenting and complaining.
It's possible that both lines might be independent sentences, and it's also possible that both lines might come together to make a single sentence. That is, both phrases in the second line might be qualities of the 'thread of the agitation of the heart'.... In both cases the meaning remains the same.
For background see S. R. Faruqi's choices. This verse is NOT one of his choices; mostly for the sake of completeness, I have added it myself. For more on Ghalib's unpublished verses, see the discussion in {4,8x}.
Well, it's not hard to see why this one didn't make it into the divan; in a ghazal with so many brilliant verses, it's definitely the runt of the litter. It feels like an assemblage of parts from two different verses, so that there's really almost no connection between the lines. It's easy to imagine a verse that would continue to develop the 'thread' and 'knot' imagery in the first line (for more on knot imagery, see {8,2}). It's also easy to imagine a verse that would make enjoyable use of the vivid idiom ;xuu;N ;xuftah , 'sleeping blood' (with thanks to Gyan Chand for explaining it)-- for example, look what Mir has done with ba;xt-e ;xuftah in M{183,13}.
But it's hard to imagine that these would be the same verse-- and sure enough, in this case they aren't.
Zamin:
In the thread of the agitation of the heart there has come to be a knot; that is, in the heart, because of weakness the strength to beat has not remained. But the construction has been a bit reversed. Instead of a knot being in the thread, into the knot there has come a thread.... In the second line the 'proof' or 'illustration' of the claim has been made: that the cause of the knot of agitation being weak is that flight is blood-dripping and broken/defeated, so that complaint is emerging only from the lips.
== Zamin, p. 400