Verse 18: And the children of Israel smote them not, (Eccles. 5:2; Ps. 15:4) because the princes of the congregation had sworn unto them by the LORD God of Israel. And all the congregation murmured against the princes.
[Because the princes had sworn] Eleazar μετὰ γερουσίας, with the Eldership, as Josephus says here, with Joshua as the originator, of course, verse 15, who may alone have had the right of obligating the people in such things (Grotius). It is uncertain whether Joshua was present for that deliberation, or indeed he himself approved their decisions at Gilgal, although there was a relation of the entire matter to him, and he even summoned the Gibeonites there: nevertheless, it is likely that the soldiers were not so insolently going to murmur against their Commander-in-Chief while he is present (Masius). The Hebrews would have been able here to mock to some extent; but, if I might make use of the words of Livy, History of Rome 3, that heedlessness of God, which prevails in the present age, had not yet arrived; nor did every one, by his own interpretation, accommodate the oath and laws to himself, but rather adapted his conduct to them (Grotius). Question 1: If they had not sworn, would it have been lawful to fall upon men voluntarily seeking peace and surrendering themselves? Response: This is answered in the negative, that is, if they had given up their name to God [as it was said]. But if that peace had been illicit, for example, so that they, as foreigners, with their superstitions preserved, might be able to live at hom, they would have been obliged to take back that peace, as offered contrary to the Law of God (Masius). Question 2: Whether this oath was valid, and obligated the Israelites? Response: Some deny this (thus Masius and Serarius and Tostatus and Augustine in Bonfrerius, Menochius). Their arguments are: 1. Because the oath was concerning a matter unlawful and prohibited. Response: But this was proven false in the comments on verse 15. 2. Because this condition appears to have been introduced into the covenant, if ye are foreigners. Response: Even if mention of this matter is made in verse 6, nevertheless this condition ought not to be supposed as thereby inserted into the contract, neither is any such thing indicated in the words in which the contract is reported (Bonfrerius). 3. Because there was a substantial error concerning a party (certain interpreters in Lapide). They were no more obligated to the Gibeonites, who feigned themselves to be foreigners, than if one erroneously promises that he is going to calculate for him that sold him nothing the value of the item sold (Masius). Response: They know that they were contracting with these, whom they had present, and the condition of one’s fatherland does not recoil upon the person; for example, if marriage is entered into with a woman that is present, which I think to be French, although she is actually Spanish, the marriage stands (Bonfrerius). 4. Because deceit invalidated it. Response: This deceit was not concerning the substance of the matter, but concerning the accidents. For, since they bestowed upon them their estates, and desire to embrace the true religion, they fulfill the substance of the covenant permitted by God, indeed, commanded by God. Therefore, there was no error of person here, but of a circumstance of the person, inasmuch as they were thinking that they lived at a distance, not near (Lapide). Nevertheless, these authors add that this oath, although it did not bind, was kept, either, 1. because God approved of its keeping. Thus Augustine, Masius, and Magalianus. But they do not show when or how this was done (Bonfrerius). Or, 2. so that they might demonstrate how important is the performance of the obligation of an oath, since they judge that that in which there is merely the appearance of an oath is not to be violated (Masius and Serarius in Bonfrerius). Those of old, as they swore sparingly, so they thought that they were obliged to keep their oaths in every respect. That in some respects both the Israelites and the Gibeonites judge that this oath is vicious is hence evident, that the former punish the deceit, the latter beg relief with respect to the deserved punishment. To me it appears that some such thing befell the Princes as what happened to Isaac when he was deceived by Jacob: For, although the request for blessing was made both in the name and person of Esau, yet neither the fraud of the one making the request nor the error of the one blessing prevented that less auspicious supplication from being esteemed both by God and Isaac as ratified and from being valid. Evidently the soul of Isaac was led by some hidden sense of Divine approbation. Likewise also in this place God so guided the spirits of the Princes that, although perhaps unintentionally, they followed God’s plan. But Divine Approbation is sufficiently evident from 2 Samuel 21:1, concerning which there has been discussion previously (Masius). Or, 3. because out of an erring conscience they thought themselves to be bound by this oath (Tostatus out of Bonfrerius). But who would believe that there was no one, not even Joshua or Eleazar, who might be able to judge concerning the obligation of the oath? or that, if they were in doubt, they would not consult God? or, how were they able to judge that there was an obligation to keep the oath, if it was against the Divine Law (Bonfrerius)? Or, 4. because, if they had broken this first covenant and oath, this would have resulted in a great scandal of the people, and in irreverence and blasphemy of God; and so to avoid these this was to be kept (Lyra). They kept the oath because they judged it to be thus expedient (certain interpreters in Bonfrerius). But the Princes assign a different reason, namely, only the obligation of the oath (Bonfrerius). Notice the we have sworn, verse 19, in the past tense; therefore, they speak of the oath, not as renewed after the deceit was acknowledged, but as originally made (Lapide). Response 2: Others affirm that this oath was valid (thus Lyra, Lapide, Bonfrerius, Suarez and Gratian in Bonfrerius). Because the substance was lawful, as was proven in the comments on verse 15. Neither does the deceit or error hinder, as was proven (Bonfrerius).
[All the common people murmured] Eager either for spoil or for vengeance, they grumble out of a desire to invade that nation (Masius). It says, all the commons; for, although among them there are many men of better character, yet by the protests of others, like bellows, they are easily inflamed unto temerity (Masius on verse 19).
All the congregation murmured against the princes: Partly, from that proneness which is in people to censure the actions of their rulers; partly, because they might think the princes by their rashness had brought them into a snare, that they could neither kill them for fear of the oath, nor spare them for fear of God’s command to the contrary; and partly, for their desire of the possession and spoil of these cities, of which they thought themselves hereby deprived.
 Hebrew: וְלֹ֤א הִכּוּם֙ בְּנֵ֣י יִשְׂרָאֵ֔ל כִּֽי־נִשְׁבְּע֤וּ לָהֶם֙ נְשִׂיאֵ֣י הָֽעֵדָ֔ה בַּֽיהוָ֖ה אֱלֹהֵ֣י יִשְׂרָאֵ֑ל וַיִּלֹּ֥נוּ כָל־הָעֵדָ֖ה עַל־הַנְּשִׂיאִֽים׃
 See Genesis 27.
 See Proverbs 21:1.
 Joshua 9:19: “But all the princes said unto all the congregation, We have sworn (נִשְׁבַּעְנוּ, in the perfect tense) unto them by the Lord God of Israel: now therefore we may not touch them.”
 Francisco Suárez (1548-1617) was a Spanish Jesuit, esteemed by some as the greatest scholastic philosopher-theologian since Thomas Aquinas. Suárez’s interests included international law, metaphysics, and theology. In the field of international law, he was a forerunner of Grotius, who speaks of him with the highest respect.
 Johannes Gratian was a theologian and canon lawyer from Bologna. He composed his Concordia discordantium canonum, commonly called Decretum Gratiani (circa 1150), to aid in the study of canon law.