When. At the height of karb — the specific distress that presses on the chest, the kind that arrives with a diagnosis, a court date, a debt with no visible way out. It is for the moment when a person can barely construct a sentence.
It asks for nothing. This is the first thing to notice and the easiest to miss. There is no request in it at all: no "grant me," no "remove this," no object named. It is a declaration repeated with different attachments. The transmitted response to being crushed is not a better-worded petition but a return to what is true regardless of the crisis, and a person who says it and then adds his own request in his own words has done nothing wrong — but the words themselves stop short deliberately.
The words. Al-'Azim is immensity, greatness of scale. Al-Halim is from hilm, the forbearance of someone who could act at once and does not — restraint that comes from strength, not from weakness or indifference. Putting the two names side by side is precise: the One being called is both able to end this immediately and not in a hurry, and both halves of that are hard to hold at once. Then Rabbul-'arshil-'azim attaches the same adjective, immense, to the Throne — and the effect is scale set against scale, the size of the trouble against something that dwarfs it.
Repetition as structure. La ilaha illallah is said, then said again with a different completion. In fuller transmitted versions further clauses follow, naming the Lord of the heavens and the earth. The sentence widens each time it repeats, and the distress does not.