שמאי אומר כל הנשים דיין שעתן. והלל אומר מפקידה לפקידה. אפילו לימים הרבה. וחכמים אומרים לא כדברי זה ולא כדברי זה. אלא מעת לעת ממעטת על יד מפקידה לפקידה. ומפקידה לפקידה ממעטת על יד מעת לעת. כל אשה שיש לה וסת. דיה שעתה. המשמשת בעדים הרי זו כפקידה. ממעטת על יד מעת לעת ועל יד מפקידה לפקידה:
Shammai says: “For all women [who begin to menstruate] it suffices [to reckon their impurity from] the time [of their discovering it].” And Hillel says: “[Their impurity 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 this one nor according to the opinion of this one, but [they are considered impure 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 regular period, it suffices [to reckon her impurity from] her set time. She who uses testing-cloths [when she has sexual relations], behold 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.