Nedarim, Chapter One, Mishnah One
Nedarim begins by clarifying the validity of substitute words used for vows. Also mentioned in this mishnah are different types of vows, all of which are mentioned in the Torah. The second part of the mishnah deals with the validity of certain statements as oaths.
1) All the substitutes for vows have the validity of vows.
a) Those for haramim have the validity of haramim,
b) And those for oaths have the validity of oaths,
c) And those for nazirite [vows] have the validity of nazirite [vows].
2) If one says to his fellow, I am forbidden from you by a vow; I am separated from you; I am distanced from you,
a) that I should eat from yours, that I should taste from yours, he is prohibited.
3) If he says: I am banned to you, Rabbi Akiba was inclined to rule stringently.
4) [If one says] As the vows of the wicked, he has vowed in respect of being a nazirite, or a sacrifice, or an oath.
a) [If he says] As the vows of the fit, he has said nothing.
b) [But if he said] As their freewill-offerings he has vowed in respect of being nazirite and a sacrifice.
Section one: A substitute formula is just as effective at making a vow as is a regular vow formula. The mishnah lists several types of vows for which this is true. The first is a neder. The second is a herem (see Leviticus 27:28). The third is an oath (shevuah). The fourth are nazirite vows.
Section two: These are all valid vow formulas, even though he doesnt formally say that the thing which he is forbidding upon himself would be like a sacrifice. In other words, a full formula would be All of your food is like a sacrifice to me. Instead he says one of the formulas in section 2, combined with one of the ones in section 2a and thus forms a vow. For instance he says, I am forbidden from you by a vow that I should eat from yours. Or I am distanced from you that I should taste from yours. In all such cases it is forbidden for the one taking a vow to subsequently eat from the other persons food.
Section three: This case is more questionable, whether the vow formula is valid. Rabbi Akiba rules that it is, but even he seems uncertain about his ruling.
Section four: If he says a regular vow formula and then tacks on at the end the words, As the vows of the wicked his vow is valid, whether it be a vow, a nazirite vow or an oath. Alternatively, there might be a nazirite walking by him and he says, Behold I am like the vows of the wicked, he is a nazirite. Or if he says, Like the vows of the wicked I shall not eat from you, he cant eat from the persons food. We can see here that vows are viewed negatively and those who vow frequently are considered to be wicked.
However, if he says, As the vows of the fit his formula is not valid, since people who are fit, do not frequently make vows. We can certainly sense here that part of the intent of this mishnah is to relate a negative message about taking frequent vows.
However, if he says, like their free-will offerings, then his vow is valid, because fit people do make vows to bring free-will offerings.