דַּבֵּ֨ר אֶֽל־אַהֲרֹ֜ן וְאֶל־בָּנָ֗יו וְאֶל֙ כָּל־בְּנֵ֣י יִשְׂרָאֵ֔ל וְאָמַרְתָּ֖ אֲלֵיהֶ֑ם זֶ֣ה הַדָּבָ֔ר אֲשֶׁר־צִוָּ֥ה יְהוָ֖ה לֵאמֹֽר׃
"Fala a Aharon e a seus filhos, e a todos os Filhos de Yisrael, e dize-lhes: Esta é a palavra que Hashem ordenou, dizendo:
Rashi
ראשי המטות [AND MOSES SPAKE TO] THE HEADS OF THE TRIBES OF THE CHILDREN OF ISRAEL] — This does not mean that he spoke only to the princes of the children of Israel and not to the people also, but that he showed respect to the princes by teaching them first and that afterwards he taught the children of Israel. This explanation seems to assume that this was the general method of instruction, but from what Biblical verse may we infer that this was so in the case of all addresses, and that this was no exceptional case? Because it says, (Exodus 34:31—32) “[And Moses called unto them], and Aaron and all the princes of the congregation returned unto him and Moses spake unto them; and afterwards all the children of Israel came nigh, [and he gave them all the commandments which the Lord had spoken to him in Mount Sinai]”. But if this be no exceptional case, what reason is there for Scripture going out of its way to state it here? Because by specially stating that the laws about vows were taught in the first instance to the princes and afterwards to the Israelites, it intends to teach that the annulling of vows is really to be effected by one person who is expert in the Law, and that only if there be no such expert, may they be annulled by three ordinary persons. But you may perhaps say that the statement does mean that Moses spoke this section only to the princes of the children of Israel, and that Moses did not speak to them also, and that consequently nothing about the expert and laymen can be inferred! But it is stated here, “This is the word”, and it is stated in the passage dealing with “animals slaughtered outside the sanctuary” (Leviticus 17:2) “This is the word”. What is the case there? It was addressed to Aaron and to his sons and to all the children of Israel, as it is said there, “Speak unto Aaron [and unto his sons and unto all the children of Israel]”! So, too, this was addressed to all of them (and the reason why it is stated here is to tell us that the annulling of vows etc., as above) (cf. Sifrei Bamidbar 153:1; Nedarim 78a).
Ramban
AND MOSES SPOKE UNTO THE HEADS OF THE TRIBES. Scripture did not precede this section with [the statement]: “And the Eternal spoke unto Moses, saying: Speak unto the heads of the tribes, and say unto them: This is the thing which the Eternal hath commanded,” as He stated in the section [dealing with] slaughtering [offerings] outside the Sanctuary Court,1Leviticus 17:2. and in other sections. Instead, He mentioned it as the end of this section, saying, These are the statutes, which the Eternal commanded Moses.2Further, Verse 17. And in the section of Vayehi Bayom Ha’shemini3Leviticus 9:1. it says: And Moses said: ‘This is the thing which the Eternal commanded that ye should do,’4Ibid., Verse 6. See also Ramban ibid. Verse 2. but did not mention the [actual] command [given by G-d to Moses] at all. Similarly, in the section about the manna [it is said], And Moses said: ‘This is the thing which the Eternal hath commanded: Let an omerful of it be kept etc.’5Exodus 16:32. [although the Divine command about it to Moses is not expressly stated].
Now the heads of the tribes of the children of Israel are the princes of the standards, whom the tribes had appointed over their standards after Nachshon the son of Amminadab [prince of the children of Judah]6Above, 2:3. and his colleagues had died. It is possible that they [the heads of the tribes referred to here] were those who are mentioned in the section [dealing with] the inheritance [of the Land]: These are the names of the men that shall take possession of the Land for you;7Further, 34:17. or it may be that those [referred to here] were others, for there Scripture speaks about [the leaders of] the future [saying] that when they come to divide up the Land [in the time of Joshua] all those mentioned will be living, and they will represent them [in the apportionment of the Land].
And Moses spoke unto the heads of the tribes. The reason [why he did not address this section to the entire people] is because it was not necessary to teach all the children of Israel that the father and husband [of a woman] can declare void those vows [of their daughter or wife, respectively] which involve affliction of the soul, and perhaps it is [even] necessary to conceal these [rights] from them, so that they should not treat vows lightly. But it was to the Sages of Israel, the heads of their tribes, that he taught the ordinance [of vows]. The verse also alludes to the interpretation of our Rabbis8Nedarim 78a. [who said] that the heads of the tribes have a special function and power in vows over and above the rest of the people, namely, that a single person who is an expert in the laws can release a person from a vow [and therefore, this section was addressed to the heads of the tribes, i.e., the Sages].
Now the [power of] release from vows [by a Sage] is not expressly stated in the Torah, but it is a law declared to Moses on Sinai, and Scripture “hung it on a hair’s-breadth,” just as the Rabbis have said:9Chagigah 10a. Now although these rules concerning the release from vows by a Sage “have nothing [in Scripture itself] on which they can be based,” they are yet on an absolute par with those laws which do have support in Scripture, as “they are all the essentials of the Torah” (ibid., 11b). “[The rules concerning] the release from vows [by a Sage] hover in the air, and have nothing [in Scripture itself] on which they can be based.” But Scripture did allude to it [by saying]: ‘lo yacheil’ (he shall not profane) his word.10Verse 3. For it did not say: “he shall not transgress his word.” but commanded that he should not make “profane” his word, meaning that he should not treat the vow as a hollow [and irreverent] thing; and when he comes to the court and they find him a cause for absolution11Thus, for example, if a man vows or swears that he will divorce his wife, the court may say to him: “Had you known that people would say about you: ‘Such is the nature of this person to divorce his wife,’ and that they will say about your daughters: ‘They are the daughters of a divorced woman! What did her mother do that she was divorced?’ [Had you known all this], would you then have made your vow?” If he says, “Had I known this I would not have made my vow,” they may release him from his vow (Nedarim 66a). See also Note 44 further on. and he regrets [having made the vow], and they release him thereof, he is not profaning it.9Chagigah 10a. Now although these rules concerning the release from vows by a Sage “have nothing [in Scripture itself] on which they can be based,” they are yet on an absolute par with those laws which do have support in Scripture, as “they are all the essentials of the Torah” (ibid., 11b). And the reason for this [law being indicated in this manner of allusion] is as I have said [above], that Scripture treated absolution from a vow or oath as if it were one of the secrets of the Torah which are only to be revealed to those who are fit to [hear] them, and therefore they are written [in the Torah] in allusion. And this section [of vows] is placed here [in the Torah] because since [in the section above] He mentioned vows to the Sanctuary, [as it is said], beside your vows, and your freewill offerings, whether they be your burnt-offerings, or your meal-offerings, or your drink-offerings, or your peace-offerings,12Above, 29:39. therefore He said furthermore: “Apart from these above-mentioned vows, there are also vows of a secular nature. [In the case of these vows, too], according to all that proceedeth out of a man’s mouth10Verse 3. he is obliged to fulfill, and to do all with which he bound his soul; for in [the case of] all vows [whether of a holy or secular nature] he shall not profane his word,10Verse 3. but others may absolve it for him” [by finding him a cause for absolution, as explained above].
Now the heads of the tribes of the children of Israel are the princes of the standards, whom the tribes had appointed over their standards after Nachshon the son of Amminadab [prince of the children of Judah]6Above, 2:3. and his colleagues had died. It is possible that they [the heads of the tribes referred to here] were those who are mentioned in the section [dealing with] the inheritance [of the Land]: These are the names of the men that shall take possession of the Land for you;7Further, 34:17. or it may be that those [referred to here] were others, for there Scripture speaks about [the leaders of] the future [saying] that when they come to divide up the Land [in the time of Joshua] all those mentioned will be living, and they will represent them [in the apportionment of the Land].
And Moses spoke unto the heads of the tribes. The reason [why he did not address this section to the entire people] is because it was not necessary to teach all the children of Israel that the father and husband [of a woman] can declare void those vows [of their daughter or wife, respectively] which involve affliction of the soul, and perhaps it is [even] necessary to conceal these [rights] from them, so that they should not treat vows lightly. But it was to the Sages of Israel, the heads of their tribes, that he taught the ordinance [of vows]. The verse also alludes to the interpretation of our Rabbis8Nedarim 78a. [who said] that the heads of the tribes have a special function and power in vows over and above the rest of the people, namely, that a single person who is an expert in the laws can release a person from a vow [and therefore, this section was addressed to the heads of the tribes, i.e., the Sages].
Now the [power of] release from vows [by a Sage] is not expressly stated in the Torah, but it is a law declared to Moses on Sinai, and Scripture “hung it on a hair’s-breadth,” just as the Rabbis have said:9Chagigah 10a. Now although these rules concerning the release from vows by a Sage “have nothing [in Scripture itself] on which they can be based,” they are yet on an absolute par with those laws which do have support in Scripture, as “they are all the essentials of the Torah” (ibid., 11b). “[The rules concerning] the release from vows [by a Sage] hover in the air, and have nothing [in Scripture itself] on which they can be based.” But Scripture did allude to it [by saying]: ‘lo yacheil’ (he shall not profane) his word.10Verse 3. For it did not say: “he shall not transgress his word.” but commanded that he should not make “profane” his word, meaning that he should not treat the vow as a hollow [and irreverent] thing; and when he comes to the court and they find him a cause for absolution11Thus, for example, if a man vows or swears that he will divorce his wife, the court may say to him: “Had you known that people would say about you: ‘Such is the nature of this person to divorce his wife,’ and that they will say about your daughters: ‘They are the daughters of a divorced woman! What did her mother do that she was divorced?’ [Had you known all this], would you then have made your vow?” If he says, “Had I known this I would not have made my vow,” they may release him from his vow (Nedarim 66a). See also Note 44 further on. and he regrets [having made the vow], and they release him thereof, he is not profaning it.9Chagigah 10a. Now although these rules concerning the release from vows by a Sage “have nothing [in Scripture itself] on which they can be based,” they are yet on an absolute par with those laws which do have support in Scripture, as “they are all the essentials of the Torah” (ibid., 11b). And the reason for this [law being indicated in this manner of allusion] is as I have said [above], that Scripture treated absolution from a vow or oath as if it were one of the secrets of the Torah which are only to be revealed to those who are fit to [hear] them, and therefore they are written [in the Torah] in allusion. And this section [of vows] is placed here [in the Torah] because since [in the section above] He mentioned vows to the Sanctuary, [as it is said], beside your vows, and your freewill offerings, whether they be your burnt-offerings, or your meal-offerings, or your drink-offerings, or your peace-offerings,12Above, 29:39. therefore He said furthermore: “Apart from these above-mentioned vows, there are also vows of a secular nature. [In the case of these vows, too], according to all that proceedeth out of a man’s mouth10Verse 3. he is obliged to fulfill, and to do all with which he bound his soul; for in [the case of] all vows [whether of a holy or secular nature] he shall not profane his word,10Verse 3. but others may absolve it for him” [by finding him a cause for absolution, as explained above].
Or HaChaim
I have come across a Baraitha in Baba Batra 120 which goes as follows: "I might have thought that Moses said this paragraph only to the princes; to prevent me from thinking this the Torah wrote זה הדבר, 'this is the thing, etc.' We have the same expression in Leviticus 17,2 where the subject is the prohibition to slaughter animals for their meat and eat them unless they had first been offered as sacrifices in the Tabernacle. This legislation applies to all the people as it is is phrased: 'any man who, etc.' We therefore use the expression זה הדבר which appears on both occasions to conclude that the legislation in our paragraph also applies to all the men of Israel." Thus far the Talmud. Granted that the exegesis of this is valid, why did the Torah then have to add the words לבני ישראל, in our verse? Clearly the Baraitha did not understand the words לבני ישראל to mean that the legislation applied to the entire people why else would it have bothered to prove this indirectly by learning the גזרה שוה (similar wording) of זה הדבר in both instances? Moreover, the Talmud in Keritut 5 told us not to treat such a גזרה שוה lightly.