Biblical Commentary on the Old Testament, by Carl Friedrich Keil and Franz Delitzsh, [1857-78], at sacred-texts.com
The Amalekites had met Israel with hostility, as the prototype of the heathen who would strive against the people and kingdom of God. But Jethro, the Midianitish priest, appeared immediately after in the camp of Israel, not only as Moses' father-in-law, to bring back his wife and children, but also with a joyful acknowledgement of all that Jehovah had done to the Israelites in delivering them from Egypt, to offer burnt-offerings to the God of Israel, and to celebrate a sacrificial meal with Moses, Aaron, and all the elders of Israel; so that in the person of Jethro the first-fruits of the heathen, who would hereafter seek the living God, entered into religious fellowship with the people of God. As both the Amalekites and Midianites were descended from Abraham, and stood in blood-relationship to Israel, the different attitudes which they assumed towards the Israelites foreshadowed and typified the twofold attitude which the heathen world would assume towards the kingdom of God. (On Jethro, see Exo 2:18; on Moses' wife and sons, see Exo 2:21-22; and on the expression in Exo 18:2, "after he had sent her back," Exo 4:26.) - Jethro came to Moses "into the wilderness, where he encamped at the mount of God." The mount of God is Horeb (Exo 3:1); and the place of encampment is Rephidim, at Horeb, i.e., at the spot where the Sheikh valley opens into the plain of er Rahah (Exo 17:1). This part is designated as a wilderness; and according to Robinson (1, pp. 130, 131) the district round this valley and plain is "naked desert," and "wild and desolate." The occasion for Jethro the priest to bring back to his son-in-law his wife and children was furnished by the intelligence which had reached him, that Jehovah had brought Israel out of Egypt (Exo 18:1), and, as we may obviously supply, had led them to Horeb. When Moses sent his wife and sons back to Jethro, he probably stipulated that they were to return to him on the arrival of the Israelites at Horeb. For when God first called Moses at Horeb, He foretold to him that Israel would be brought to this mountain on its deliverance from Egypt (Exo 3:12).
(Note: Kurtz (Hist. of O. C. iii. 46, 53) supposes that it was chiefly the report of the glorious result of the battle with Amalek which led Jethro to resolve to bring Moses' family back to him. There is no statement, however, to this effect in the biblical text, but rather the opposite, namely, that what Jethro had heard of all that God had done to Moses and Israel consisted of the fact that Jehovah had brought Israel out of Egypt. Again, there are not sufficient grounds for placing the arrival of Jethro at the camp of Israel, in the desert of Sinai and after the giving of the law, as Ranke has done. For the fact that the mount of God is mentioned as the place of encampment at the time, is an argument in favour of Rephidim, rather than against it, as we have already shown. And we can see no force in the assertion that the circumstances, in which we find the people, point rather to the longer stay at Sinai, than to the passing halt at Rephidim. For how do we know that the stay at Rephidim was such a passing one, that it would not afford time enough for Jethro's visit? It is true that, according to the ordinary assumption, only half a month intervened between the arrival of the Israelites in the desert of Sin and their arrival in the desert of Sinai; but within this space of time everything might have taken place that is said to have occurred on the march from the former to the latter place of encampment. It is not stated in the biblical text that seven days were absorbed in the desert of Sin alone, but only that the Israelites spent a Sabbath there, and had received manna a few days before, so that three or four days (say from Thursday to Saturday inclusive) would amply suffice for all that took place. If the Israelites, therefore, encamped there in the evening of the 15th, they might have moved farther on the morning of the 19th or 20th, and after a two days' journey by Dofkah and Alush have reached Rephidim on the 21st or 22nd. They could then have fought the battle with the Amalekites the following day, so that Jethro might have come to the camp on the 24th or 25th, and held the sacrificial meal with the Israelites the next day. In that case there would still be four or five days left for him to see Moses sitting in judgment a whole day long (Exo 18:13), and for the introduction of the judicial arrangements proposed by Jethro; - amply sufficient time, inasmuch as one whole day would suffice for the sight of the judicial sitting, which is said to have taken place the day after the sacrificial meal (Exo 18:13). And the election of judges on the part of the people, for which Moses gave directions in accordance with Jethro's advice, might easily have been carried out in two days. For, on the one hand, it is most probable that after Jethro had watched this severe and exhausting occupation of Moses for a whole day, he spoke to Moses on the subject the very same evening, and laid his plan before him; and on the other hand, the execution of this plan did not require a very long time, as the people were not scattered over a whole country, but were collected together in one camp. Moreover, Moses carried on all his negotiations with the people through the elders as their representatives; and the judges were not elected in modern fashion by universal suffrage, but were nominated by the people, i.e., by the natural representatives of the nation, from the body of elders, according to their tribes, and then appointed by Moses himself. - Again, it is by no means certain that Israel arrived at the desert of Sinai on the first day of the third month, and that only half a month (15 or 16 days) elapsed between their arrival in the desert of sin and their encamping at Sinai (cf. Exo 19:1). And lastly, though Kurtz still affirms that Jethro lived on the other side of the Elanitic Gulf, and did not set out till he heard of the defeat of the Amalekites, in which case a whole month might easily intervene between the victory of Israel and the arrival of Jethro, the two premises upon which this conclusion is based, are assumptions without foundation, as we have already shown at Exo 3:1 in relation to the former, and have just shown in relation to the latter.)
When Jethro announced his arrival to Moses ("he said," sc., through a messenger), he received his father-in-law with the honour due to his rank; and when he had conducted him to his tent, he related to him all the leading events connected with the departure from Egypt, and all the troubles they had met with on the way, and how Jehovah had delivered them out of them all. Jethro rejoiced at this, and broke out in praise to Jehovah, declaring that Jehovah was greater than all gods, i.e., that He had shown Himself to be exalted above all gods, for God is great in the eyes of men only when He makes known His greatness through the display of His omnipotence. He then gave a practical expression to his praise by a burnt-offering and slain-offering, which he presented to God. The second כּי in Exo 18:11 is only an emphatic repetition of the first, and אשׁר בּדּבר is not dependent upon ידעתּי, but upon גּדול nopu tub, or upon הגדּיל understood, which is to be supplied in thought after the second כּי: "That He has proved Himself great by the affair in which they (the Egyptians) dealt proudly against them (the Israelites)." Compare Neh 9:10, from which it is evident, that to refer these words to the destruction of Pharaoh and his army in the Red Sea as a punishment for their attempt to destroy the Israelites in the water (Exo 1:22) is too contracted an interpretation; and that they rather relate to all the measures adopted by the Egyptians for the oppression and detention of the Israelites, and signify that Jehovah had shown Himself great above all gods by all the plagues inflicted upon Egypt down to the destruction of Pharaoh and his army in the Red Sea.
The sacrifices, which Jethro offered to God, were applied to a sacrificial meal, in which Moses joined, as well as Aaron and all the elders. Eating bread before God signified the holding of a sacrificial meal, which was eating before God, because it was celebrated in a holy place of sacrifice, where God was supposed to be present.
The next day Jethro saw how Moses was occupied from morning till evening in judging the people, who brought all their disputes to him, that he might settle them according to the statutes of God. על עמד: as in Gen 18:8. The people came to Moses "to seek or inquire of God" (Gen 18:15), i.e., to ask for a decision from God: in most cases, this means to inquire through an oracle; here it signifies to desire a divine decision as to questions in dispute. By judging or deciding the cases brought before him, Moses made known to the people the ordinances and laws of God. For every decision was based upon some law, which, like all true justice here on earth, emanated first of all from God. This is the meaning of Gen 18:16, and not, as Knobel supposes, that Moses made use of the questions in dispute, at the time they were decided, as good opportunities for giving laws to the people. Jethro condemned this plan (Gen 18:18.) as exhausting, wearing out (נבל lit., to fade away, Psa 37:2), both for Moses and the people: for the latter, inasmuch as they not only got wearied out through long waiting, but, judging from Gen 18:23, very often began to take the law into their own hands on account of the delay in the judicial decision, and so undermined the well-being of the community at large; and for Moses, inasmuch as the work was necessarily too great for him, and he could not continue for any length of time to sustain such a burden alone (Gen 18:18). The obsolete form of the inf. const. עשׂהוּ for עשׂתו is only used here, but is not without analogies in the Pentateuch. Jethro advised him (Gen 18:19.) to appoint judged from the people for all the smaller matters in dispute, so that in future only the more difficult cases, which really needed a superior or divine decision, would be brought to him that he might lay them before God. "I will give thee counsel, and God be with thee (i.e., help thee to carry out this advice): Be thou to the people האלהים מוּל, towards God," i.e., lay their affairs before God, take the place of God in matters of judgment, or, as Luther expresses it, "take charge of the people before God." To this end, in the first place, he was to instruct the people in the commandments of God, and their own walk and conduct (הזהיר with a double accusative, to enlighten, instruct; שדרך the walk, the whole behaviour; מעשׂה particular actions); secondly, he was to select able men (חיל אנשׁי men of moral strength, Kg1 1:52) as judges, men who were God-fearing, sincere, and unselfish (gain-hating), and appoint them to administer justice to the people, by deciding the simpler matters themselves, and only referring the more difficult questions to him, and so to lighten his own duties by sharing the burden with these judges. מעליך הקל (Gen 18:22) "make light of (that which lies) upon thee." If he would do this, and God would command him, he would be able to stand, and the people would come to their place, i.e., to Canaan, in good condition (בּשׁלום). The apodosis cannot begin with וצוּך, "then God will establish thee," for צוּה never has this meaning; but the idea is this, "if God should preside over the execution of the plan proposed."
Moses followed this sage advice, and, as he himself explains in Deu 1:12-18, directed the people to nominate wise, intelligent, and well-known men from the heads of the tribes, whom he appointed as judges, instructing them to administer justice with impartiality and without respect of persons.
The judges chosen were arranged as chiefs (שׂרים) over thousands, hundreds, fifties, and tens, after the analogy of the military organization of the people on their march (Num 31:14), in such a manner, however, that this arrangement was linked on to the natural division of the people into tribes, families, etc. (see my Archologie, 140). For it is evident that the decimal division was not made in an arbitrary manner according to the number of heads, from the fact that, on the one hand, the judges were chosen from the heads of their tribes and according to their tribes (Deu 1:13); and on the other hand, the larger divisions of the tribes, viz., the families (mishpachoth), were also called thousands (Num 1:15; Num 10:4; Jos 22:14, etc.), just because the number of their heads of families would generally average about a thousand; so that in all probability the hundreds, fifties, and tens denote smaller divisions of the nation, in which there were about this number of fathers. Thus in Arabic, for example, "the ten" is a term used to signify a family (cf. Hengstenberg, Dissertations v. ii. 343, and my Arch. 149). The difference between the harder or greater matters and the smaller matters consisted in this: questions which there was not definite law to decide were great or hard; whereas, on the other hand, those which could easily be decided from existing laws or general principles of equity were simple or small. (Vide Joh. Selden de Synedriis i. c. 16, in my Arch. 149, Not. 3, where the different views are discussed respecting the relative positions and competency of the various judges, about which there is no precise information given in the law.) So far as the total number of judges is concerned, all that can be affirmed with certainty is, that the estimated number of 600 judges over thousands, 6000 over hundreds, 12,000 over fifties, and 60,000 over tens, in all 78,600 judges, which is given by Grotius and in the Talmud, and according to which there must have been a judge for every seven adults, is altogether erroneous (cf. J. Selden l.c. pp. 339ff.). For if the thousands answered to the families (Mishpachoth), there cannot have been a thousand males in every one; and in the same way the hundreds, etc., are not to be understood as consisting of precisely that number of persons, but as larger or smaller family groups, the numerical strength of which we do not know. And even if we did know it, or were able to estimate it, this would furnish no criterion by which to calculate the number of the judges, for the text does not affirm that every one of these larger or smaller family groups had a judge of its own; in fact, the contrary may rather be inferred, from the fact that, according to Deu 1:15, the judges were chosen out of the heads of the tribes, so that the number of judges must have been smaller than that of the heads, and can hardly therefore have amounted to many hundreds, to say nothing of many thousands.