Khalq (creation) means bringing a thing or act from nonexistence into existence. Fiʿl (act) names the action as performed and attributed to an agent. Kasb (acquisition) concerns the servant's voluntary relation to that act, grounding obligation and accountability.
Consider someone giving charity. The act and its occurrence fall under divine creation, but the person undertakes it with intention and choice; this is why the act can count as worship or wrongdoing according to its circumstances. Confusing these relations produces a false dilemma: either the servant is a mere automaton or an independent creator.
Sunni theologians differ over the detailed explanation of acquisition, but share the concern to preserve both divine creation and meaningful human responsibility.