If you make a neder (a personal vow), is following it considered a matter of Biblical (d'oraysa) or Rabbinical (d'rabbanan) law? Please bring sources.
1 Answer
It depends on the circumstances. Obviously, n'darim in general are a matter of biblical law: they're mentioned in the Tora. Yad, N'darim 1:4. On the other hand, some rules were established by the rabbis as safeguards against violating biblical laws of n'darim. Ibid., :27.