What is the rhetorical point in “فَمَا رَبِحَتْ تِجَارَتُهُمْ”?

ʿIlm al-Maʿānī: Predication, Emphasis, and Rational Metaphor

• The making of profit is attributed to the trade itself
• It contains no negation
• It must only be an explicit metaphor
• There is no predication