Nedarim 17a (יז.) — the Talmud in English

The verse states

in the passage concerning the offering for an oath of utterance: “Or if a person swears, expressing with his lips

to do harm or to do good,”

just as

“doing good”

is optional, so too

“doing harm”

is optional; one who swore to annul a mitzva but did not annul it is excluded, for he does not have the authority to do so.

And since this is so, why do we need to derive this law from “He shall not profane his word,” which implies: but he may profane matters concerning Heaven?!

And we answer:

one verse—

“to do harm or to do good,” stated in the passage concerning the offering for an oath of utterance—

serves to exempt him from the offering for an oath;

but we still would not know that he also does not violate the prohibition of “He shall not profane his word,” since the exclusion is stated in the passage concerning the offering for an oath.

And one

verse—“He shall not profane his word,” but he may profane matters concerning Heaven—

serves to exempt him from the prohibition of an oath—

namely, from “He shall not profane his word.”

Mishna:

Another distinction between a vow and an oath is explained in our Mishna: the imposition of two vows one upon the other, as opposed to the imposition of two oaths one upon the other.

There is a vow

that takes effect

within

a

vow.

But an oath

does not take effect

within

an

oath.

How so?

If he made two vows of nazirite observance, for example, if he

said: I am a nazirite

if I eat

this loaf of bread, and he then said

I am a nazirite if I eat

this loaf,

and he ate

the loaf—he is

liable

to observe two periods of nazirite observance, one after the other,

for each and every one

of his two statements, “I am a nazirite.”

But if he swore twice, saying:

An oath that I will not eat

this loaf, and he again swore:

An oath that I will not eat

this loaf

, and he ate—he is

liable only

for

one oath.

Gemara:

Rav Huna said: They taught

in our Mishna that both periods of nazirite observance take effect

only

in a case where

he said: I am a nazirite today

and then said

I am a nazirite tomorrow.

Since an additional day is added

because he added an extra day to the second period of nazirite observance beyond the first period, and his second period of nazirite observance takes effect on that day,

one period of nazirite observance takes effect upon another period of nazirite observance.

However,

if

he said: I am a nazirite today,

and then said

I am a nazirite today,

since he added nothing to his second period of nazirite observance—

one period of nazirite observance does not take effect upon another period of nazirite observance.

And Shmuel said: Even if he said “

I am a nazirite today,” “

I am a nazirite today”—

the nazirite observance takes effect upon him

upon it.

And we raise an objection:

But according to Rav Huna,

who said that if he added nothing to his second period of nazirite observance, the second period of nazirite observance does not take effect upon him, this is difficult:

Rather than having the tanna teach,

in the place where the tanna taught in our Mishna the distinction between an oath and a vow—that there is a vow within a vow, but

there is no oath within an oath—

let him teach

this distinction with regard to vows themselves:

There is a vow within a vow, but there is no vow within a vow.

How so?

If he said, “

I am a nazirite today,” “

I am a nazirite tomorrow”—

there is a vow within a vow.

But if he said, “

I am a nazirite today,” “

I am

a nazirite today”—