If we think about Hume as a happy go lucky person who loved port and cheese, we can pull two strands of his thinking that nicely reflect his world view. The first strand, was his understanding that commerce was a humanizing force. His point was that the desire to improve one's material condition gives a person something useful to do, stops them being "indolent" and it drives the interactions that result in "industry, art and knowledge."
Hume's second strand was his understanding of 'habit' which he read as a scaffolding of both 'custom and habit' which allowed for the individual who gets useful things done. Hume's list of good things for such an individual, included stable laws and property rights, not because they were divine rights, but because they provided a predictable framework in which human beings could cooperate, and flourish without butchering each other.
"What happened?"
The likes of Descartes and that man from Somerset John Locke were of the opinion that we people had a rigid soul. Our core essence was rational and fixed, they argued, we were isolated, autonomous moral actors, we were "absolute" which means our self, the thing that is you or I, doesn't change.
Hume, on the other hand, with his ever changing bundle of emotions and passions, his constantly fleeting thoughts did not believe that reason alone could even begin to prove the existence of an unchanging self, the existence of God or morality or half the things reason was credited with.
It was like this : reason and passion are not enemies. But as Hume put it himself : "Reason is, and ought only to be, the slave of the passions."
For Hume, commercial activity was something individuals could do that was only valuable because it refined human sociability and made life pleasant without us butchering each other. The moment commercial individualism starts laying down endless no's, destroys social harmony, conversation, and sympathy, Hume would have agreed, commercial individualism begins to defeat its own purpose.
