FWP:
SETS == IDIOMS; SYMMETRY
For background see S. R. Faruqi's choices. This verse is NOT one of his choices; I thought it was interesting and have added it myself. For more on Ghalib's unpublished verses, see the discussion in {4,8x}.
Here's an elegant example of the power of 'symmetry' (if A=B, then B=A). Zamin seems to read (2b): he feels that Farhad is being denigrated as a mere stone-cutter without fervor of the heart. Gyan Chand seems to read (2a): he feels that even the laziest, worst worker can, like Farhad, succeed through fervor of the heart.
In the first line, the knots 'of' action are the inner tangles, perplexities, etc. (on 'knot' verses see {8,2}) that prevent one from getting things done. Apparently the agitation of the heart has been so powerful that it has burst open these 'knots' and been able to accomplish its proper work in the world. It has accomplished even more than Farhad in that regard.
But of course the question then arises-- what exactly did Farhad accomplish? (For his story, see {1,2}.) Ultimately, he split his head open with his own axe, so in a worldly sense he failed to accomplish his intended tasks (of cutting through the mountain, of gaining Shirin). But since we're in the ghazal world, it's equally true that he succeeded in his 'task' as a lover-- he was faithful to the highest degree, and unhesitatingly died in the service of his beloved; what more could be expected of any true lover?
Thus it's quite possible that what the agitated heart accomplished, by bursting open its knots, was its own death. That was its 'work', its task, its action-- just as it was Farhad's, except that Farhad was more dilatory and less efficient.
Then, what does 'here' mean? At a minimum, where the speaker is. Or where true lovers are? Or in this world, where we all try so hard and achieve (outwardly?) so little?
This verse belongs to the 'snide remarks about famous lovers' group; for others, see {100,4}.
Zamin:
mazduur-e sangii;N-dast = a lazy worker
That is, through a small movement of the heart, very great actions are set in motion, such that even the stone-breaker Farhad could not have effected them. The gist is that those tasks that can be done through strength of will and firm resolve, cannot be done through strength of arm. As good as the theme is, equally clumsy is the construction, and the expression too is incomplete.
== Zamin, p. 239