أن صرف العبد قدرته وإرادته إلى الفعل كسب، وإيجاد الله تعالى الفعل عقب ذلك خلق
The servant's directing capacity and will toward an action is acquisition, while God's bringing the action into existence is creation.
Ṣarf means applying or directing one's capacity and will. In this account the human element is not merely a label: the act can be meaningfully attributed to the agent for praise or blame.
The phrase following that should not be mistaken for a period of creative independence or a necessity imposed on God. It distinguishes the human involvement from the divine bringing-into-existence of the event.