When. In the gap between finishing something and learning how it went — the days after an exam, an interview, a scan. It is the short form of a longer supplication that lists eight things; these four are the ones that describe waiting.
The words. A'udhu bika — 'I take refuge in You'. Note the object: the refuge is in a person, not from a feeling. Nothing here asks for the anxiety to be deleted; it asks to be held somewhere while it runs.
Two pairs, two axes. Hamm and hazan divide time between them. Hamm faces forward, at the result not yet posted. Hazan faces back, at the question answered badly and the hour wasted. Waiting produces both at once, alternating, which is why they are named together. Then ajz and kasal divide capacity. Ajz is not being able; kasal is not wanting to. Someone waiting on a result slides between them without noticing: the week is lost either way, and the person cannot always tell which one is holding him.
Why this state and not the result. The supplication says nothing about the outcome. It does not ask for a pass, a good report, an offer. It treats the waiting itself as the thing worth taking refuge from, which is an unusual reordering and a truthful one — the outcome is fixed already; only the waiting is still live.
A note. The longer form continues into miserliness, cowardice, debt and being overpowered. Saying these four alone is a recognised form and not a fragment of something owed.