[If the owner said,] `where is my ox?` and he replied to him, `I do not know what you say,` whereas it died or was injured or captured or stolen or lost; [and the owner said,] `I adjure you,` and he said, `Amen,` He is liable. If he said to a paid guardian, or Hirer. `where is my ox?` and he replied to him, `it died,` whereas it was injured or captured; [or he replied,] `it was injured,` whereas it died or was captured; [or he replied,] `it was captured,` whereas it died or was injured; [or he replied,] `it was stolen, whereas it was lost; [or he replied,] `it was lost,` whereas it was stolen; [and the owner said,] `I adjure you,` and he said, `Amen,` He is exempt. [If he replied,] `it died,` or, `it was injured,` or, `it was captured,` whereas it was stolen or lost; [and the owner said,] `I adjure you.` and he said, `Amen,` He is liable. [If he replied,] `it was lost,` or, `it was stolen,` whereas it died or was injured or captured; [and the owner said,] `I adjure you,` and he said, `Amen,` He is exempt. This is the principle: He who [by lying] changes from liability to liability. Or from exemption to exemption, or from exemption to liability, is exempt; from liability to exemption, is liable. This is the principle: He who takes an oath to make it more lenient for himself, is liable; to make it more stringent for himself, is exempt.

 שבועות 8.6
איכן שורי, ואמר לו איני יודע מה אתה סח, והוא שמת או נשבר או נשבה או נגנב או אבד-- משביעך אני, ואמר אמן-- חייב׃
אמר לנושא שכר ולשוכר איכן שורי, ואמר לו מת, והוא שנשבר או נשבה, נשבר, והוא שמת או נשבה, נשבה, והוא שמת או נשבר, נגנב, והוא שאבד, אבד, והוא שנגנב-- משביעך אני, ואמר אמן-- פטור׃ מת או נשבה או נשבר, והוא שנגנב או שאבד-- משביעך אני, ואמר אמן-- חייב׃ אבד או נגנב, והוא שמת או נשבר או נשבה-- משביעך אני, ואמר אמן-- פטור׃ זה הכלל-- כל הנשבע להקל על עצמו, חייב; להחמיר על עצמו, פטור.

Shammai says: for all women [who become menstruous] it suffices [to reckon their uncleanness from] the time [of their discovering it] and Hillel Says: [their uncleanness is reckoned backwards] from the [last] examination to the [previous] examination, even if this covers many days. But the Sages say: neither according to the opinion of the one nor according to the opinion of the other, but [they are considered unclean for] the past twenty four hours when this lessens the period from the [last] examination to the [previous] examination, and for the period from the [last] examination to the [previous] examination when this lessens the past twenty-four hours. Any woman who has a settled period, it suffices [to reckon her uncleanness from] Her set time. She who uses testing-cloths when she has marital connexion, Lo, this is like an examination: it lessens either the period of the [past] twenty four hours or the period from the [last] examination to the [previous] examination.

עדייות 1.1
שמאי אומר, כל הנשים, דיין שעתן; הלל אומר, מפקידה לפקידה, אפילו לימים הרבה׃ וחכמים אומרין, לא כדברי זה ולא כדברי זה; אלא מעת לעת ממעטת על יד מפקידה לפקידה, ומפקידה לפקידה ממעטת על יד מעת לעת׃ כל אישה שיש לה וסת, דייה שעתה; והמשמשת בעידים-- הרי זו כפקידה, וממעטת על יד מעת לעת ועל יד מפקידה לפקידה