Is the prohibition of melacha on Chol HaMoed from the Torah or rabbinic? We’ll explore both sides of the debate—and why it matters. The nafka mina is huge: if it’s d’Oraisa, any doubt must be treated strictly (safek d’Oraisa l’chumra). If it’s d’Rabbanan, we’re lenient in cases of doubt. It also affects whether one may benefit from melacha done improperly and how seriously we treat violations. This episode breaks down the core question and its real-world halachic impact.