«سَمْحُ الْبَدِيهَةِ لَيْسَ يُمْسِكُ لَفْظَهُ فَكَأَنَّمَا أَلْفَاظُهُ مِنْ مَالِهِ»
He speaks freely and holds back no words, as though his words were part of his wealth.
The overt praise concerns ready, fluent expression; comparing words to wealth simultaneously suggests generosity. This is called istitibaʿ, in which one commendation brings a second commendation along with it.
It is a special type of semantic embedding: not every instance of idmaj is praise, whereas istitibaʿ is specifically tied to an additional favorable quality.