مَا تَعْمَلُونَ
“What you fashion” or “your doing”: the meaning differs with the grammatical analysis.
On the verbal-noun construction, taʿmalūn is understood in the sense of the act of doing, approximately “your action.” On the relative-pronoun construction, the expression points to the object acted upon or fashioned. These readings therefore do not produce exactly the same argument.
This is an example of why syntax, immediate context, and the logical claim need to be considered together. The text's theological conclusion should not be made to depend on concealing a real grammatical alternative.