والمقصود تعميم إرادة الله تعالى وقدرته
The point is to affirm the universal scope of God's will and power.
In this Sunni formulation, no possible event that actually occurs stands independently outside divine power and volition. Exempting an occurrence from that scope would introduce an independent exception to divine creative sovereignty. The argument concerns the existence of an event, not whether its occurrence is morally permissible.
A human lie is an event in the world created by God, yet lying is not therefore authorized. Only by distinguishing creative volition from revealed command can both statements be maintained without contradiction.