When. By someone under a debt he cannot see his way out of. It was taught to a man carrying an obligation he could not meet, and it is said as a standing supplication rather than only at the moment a payment falls due.
The words. Ikfini bihalalika an haramik. The verb is kafa, to suffice, and it is followed by an — 'suffice me with Your lawful away from Your unlawful'. That preposition changes the request. It is not asking for enough lawful income; it is asking for an amount of lawful income sufficient to turn a person away from the other door. Anyone in debt knows the door meant: the loan with interest, the shortcut, the thing done for money.
The second half. Aghnini bifadlika amman siwak — 'enrich me by Your bounty away from everyone besides You'. Again the request is aimed at a relationship, not a sum. What is asked for is independence from creditors, family who lend with a face, employers who own you by the month. And bifadlika, by Your bounty: not by my earning, not by my cleverness.
What is not in it. No amount, no deadline, no promise that the debt will be cleared by a date. The supplication reorders what is being asked for — the freedom rather than the figure.
Alongside the asking. It sits with the ordinary means: repaying what can be repaid, telling the creditor the truth, cutting what can be cut. The words are not offered as a replacement for any of that.