«وَمَا لَنَا لَا نُؤْمِنُ بِاللَّهِ»
Why should we not believe in Allah?
This Qur’anic expression illustrates a related negative imperfect construction. The source also distinguishes the occurrence signaled by affirmative past from the non-occurrence expressed by negative past. Negation can alter how a clause relates to the reference event and therefore affect the linking rules.
Example: “Dakhala al-rajulu wa-lam yatakallam” — The man entered without speaking. It tells us that a possible or expected action did not occur at the relevant time. The acceptability and effect of wāw must be understood with polarity and temporal reference, not as a single rule for every past-tense clause.