What two major things were samurai restricted from participating in and why?

They were forbidden from being involved in entertainment or trade (commerce)

Well, as a patriot our strengths are that we know this land, our families are at stake, and that we fight for what we believe in. We will win this war because we are fighting for what we think is right. Unlike the British redcoats who are fighting because their king has made them. If we lose this fight the lives of our families are at stake and the mercy to the redcoats as well as our posterity.