He defines his livelihood not as commerce or a manual craft but as study, scholarship, eloquent prose, and poetry. His answer is that learning and composition constitute a genuine skill.
«وَرَأْسُ مَالِي سِحْرُ الْكَلَامِ»
My capital is the enchanting power of speech.
“Capital” is borrowed from the language of business. “The magic of speech” describes the extraordinary appeal of eloquence, not literal sorcery.
The wife demands income from a trade; the husband responds by arguing that literary skill itself is a trade.