The opening mishnah of Tractate Peah lists mitzvot that have no defined measure: the area of the corner of one’s field that is left unharvested (so that the crops can be collected by those in need), the quantity of first-fruits that are brought to the Temple on Shavuot, the size ot the offering that one brings when visiting the Temple on a pilgrimage festival, the number of acts of loving-kindness one performs, and the time one dedicates to the study of the Torah.
Implied in this teaching is that all of the rest are quantifiable. The rabbis of the Talmud spent enormous time and energy establishing the quantities, measurements and limits that shape halakhah, including important details that do not appear in the Torah: How tall should a sukkah be? At least 10 handbreadths tall and not more than 20 cubits. What is the minimum acceptable volume of water in a mikveh? Forty seah, or about 90 gallons. How much food does one have to eat in order to be satisfied and become obligated to say the Grace after Meals? Some say the volume of an olive; others say that of an egg. How long is a standard naziriteship? Thirty days. And so on, and so on.
Just as the rabbis quantified positive commandments, they also quantified prohibitions, especially when it comes to eating and drinking. Take Yom Kippur, for example. Granted that it is forbidden to eat on Yom Kippur, but how much food must one eat to have violated the prohibition? Mishnah Yoma 8:2 provides the answer:
One who eats a quantity equivalent in volume to a large date and its pit, or who drinks a cheekful of liquid is liable.
But what if one eats half a date-bulk of food and drinks half a cheek full of water? Is that the same as eating a full date-bulk or drinking a cheekful? The mishnah says no:
All foods that one eats join together to constitute a date-bulk; and all liquids that one drinks join together to constitute a cheekful. However, if one eats and drinks, the food and beverage do not join together.
In other words, the prohibition from eating is distinct from the prohibitions of drinking; therefore, quantities of food and drink do not combine. Each is measured on its own.
This is also the case when prohibited food gets mixed up with permitted food. If one eats an olive-bulk of food that is 50% permitted and 50% prohibited, one does not become liable for eating prohibited food. Although one has eaten them together, the two types of food do not combine. Only the quantity of forbidden food counts toward any potential violation and, in this case, since only half an olive bulk was consumed, the threshold has not been met.
This is the general rule regarding prohibitions: Two types of prohibitions don’t combine (like eating and drinking on Yom Kippur), and permitted substances do not combine with prohibited ones. The exception to this rule is the case of the nazir, as we learn about on today’s daf:
Rabbi Abbahu says that Rabbi Yohanan says: With regard to all prohibitions that are written in the Torah, a permitted substance does not combine with a forbidden substance. This principle applies to all halakhot except for the prohibitions of a nazirite.
What does this mean? If, for example, only a few drops of grade juice (less than an olive-bulk) drip onto a piece of bread, they combine with that bread to produce a food item larger than an olive-bulk that is forbidden to a nazirite.
This ruling did not come about as the result of an imaginative midrashic interpretation or because the rabbis decided to be stringent with nazirites. Rather, it’s set out in the Torah:
If anyone, man or woman, explicitly utters a nazirite’s vow, to set themselves apart for God, they shall abstain from wine and any other intoxicant; they shall not drink vinegar of wine or of any other intoxicant, neither shall they drink anything in which grapes have been steeped, nor eat grapes fresh or dried. (Numbers 6:2–3)
As the verse makes clear, it’s not just that a nazir is prohibited from consuming grape products, they are also prohibited from consuming products that “have been steeped” in grape products. The specific language used by the Torah suggests a unique standard. And so, the usual threshold for what constitutes eating and drinking does not apply in this case.
The strictness of this rule is another reason that it’s a good idea for potential nazirites to know what they are getting into (or, as the punny might say, they should be steeped in knowledge), before taking on a nazirite vow.
Read all of Nazir 35 on Sefaria.