Shevuos 4:1-2

Shevuos 4:1

An oath of testimony (i.e., that one does not possess information relevant to a case) only applies to men, not to women; it applies to those unrelated to the litigants, not to relatives; it applies to those who are qualified to testify, not to those who have been disqualified; it applies only to those who are appropriate to testify (excluding, for example, the king). One can violate such an oath regardless of whether or not it was made in front of the court so long as he made the oath on his own. If the oath was imposed upon him by others, he is not liable until he denies possessing information in front of the court; this is the opinion of Rabbi Meir. The Sages say that whether one made an oath on his own or whether it was imposed upon him by others, he is not liable until he denies having information in front of the court.

Shevuos 4:2

One is liable for intentionally violating an oath of testimony and for unintentionally violating it if he intentionally denied the testimony. One is not liable if he unintentionally denied the testimony. For intentional violation of the oath, one must bring a korban oleh v’yoreid (variable offering).