kufr : 'Unbelief, infidelity; incredulity; scepticism; ingratitude; paganism, idolatry; impiety, blasphemy'. (Platts p.839)
hujuum : 'Rushing (upon, or at, - par ); attacking; ... — assault, attack; effort; impetuosity; — crowd, throng, concourse, mob'. (Platts p.1221)
laa-chaar : 'Without remedy, helpless, powerless; ... destitute, forlorn, poor; — without excuse; at a loss; without an alternative, having no alternative; under constraint, under pressure of necessity, perforce; compelled, forced'. (Platts p.944)
That is, in our heart longings are many. But the longings are helpless because their fulfilment is in the power of someone else. That is, the fulfillment or non-fulfilment of our desires is in the hand of the rulers of fate and destiny, and is dependent on the Divine will. Then to complain against the Divine will will be unbelief/ingratitude. And to ask for something in prayer (beyond what has been written in our fate) is ungratefulness.
Asad, my longings are extremely numerous. Some longings have already been fulfilled, so to complain to the Lord is unbelief/ingratitude. And to pray for the fulfilment of more purposes shows that you are not thankful for what you have received. I am prepared for those accusations, because compared to my fulfilled longings, my unfulfilled longings are greatly much more numerous.
For more on Ghalib's unpublished verses, see the discussion in {4,8x}. See also the overview index.
This verse is pretty straightforward. The first line recognizes the sinfulness of repining against the Divine will. Then the second line both does, and doesn't, apologize for repining. The blame is shifted to a massive assault by longings, but whose longings are they, anyway?
Compare {219,1}, the archetypal verse about the painful abundance of longings.
Asi:
Oh Asad, although it is our belief that to complain is unbelief/ingratitude, and to pray is ungratefulness, what can we do? For from the crowd/assult of longings, we are helpless. Under duress, we are compelled to complain, and also to pray.
== Asi, p. 159