والخطاب مثبت لوجوب الأداء، ومعروف للعبد سبب الوجوب قبله
The legal address establishes performance duties, while the outward cause makes their occasion identifiable.
Knowing a general duty and reaching the occasion for its specific performance need not coincide. A person knows in the morning that Zuhr prayer is obligatory, but the particular obligation is not discharged until its appointed time.
The key distinction is between knowledge of a command and the arrival of the cause that makes this individual performance due.