Biblical Commentary on the Old Testament, by Carl Friedrich Keil and Franz Delitzsh, [1857-78], at sacred-texts.com
Deuteronomy Chapter 13
The first case. If a prophet, or one who had dreams, should rise up to summon to the worship of other gods, with signs and wonders which came to pass, the Israelites were not to hearken to his words, but to put him to death. The introduction of חלום חלם, "a dreamer of dreams," along with the prophet, answers the two media of divine revelation, the vision and the dream, by which, according to Num 12:6, God made known His will. With regard to the signs and wonders (mopheth, see at Exo 4:21) with which such a prophet might seek to accredit his higher mission, it is taken for granted that they come to pass (בּוא); yet for all that, the Israelites were to give no heed to such a prophet, to walk after other gods. It follows from this, that the person had not been sent by God, but as a false prophet, and that the signs and wonders which he gave were not wonders effected by God, but σημεῖα καὶ τέρατα ψεύδους ("lying sings and wonders," Th2 2:9); i.e., not merely seeming miracles, but miracles wrought in the power of the wicked one, Satan, the possibility and reality of which even Christ attests (Mat 24:24). - The word לאמר, saying, is dependent upon the principal verb of the sentence: "if a prophet rise up...saying, We will go after other gods."
God permitted false prophets to rise up with such wonders, to try the Israelites, whether they loved Him, the Lord their God, with all their heart. (נסּה as in Gen 22:1.) אהבים הישׁכם, whether ye are loving, i.e., faithfully maintain your love to the Lord. It is evident from this, "that however great the importance attached to signs and wonders, they were not to be regarded among the Israelites, either as the highest test, or as absolutely decisive, but that there was a certainty in Israel, which was so much the more certain and firm than any proof from miracles could be, that it might be most decidedly opposed to it" (Baumgarten). This certainty, however, was not "the knowledge of Jehovah," as B. supposes; but as Luther correctly observes, "the word of God, which had already been received, and confirmed by its own signs," and which the Israelites were to preserve and hold fast, without adding or subtracting anything. "In opposition to such a word, no prophets were to be received, although they rained signs and wonders; not even an angel from heaven, as Paul says in Gal 1:8." The command to hearken to the prophets whom the Lord would send at a future time (Deu 18:18.), is not at variance with this: for even their announcements were to be judged according to the standard of the fixed word of God that had been already given; and so far as they proclaimed anything new, the fact that what they announced did not occur was to be the criterion that they had not spoken in the name of the Lord, but in that of other gods (Deu 18:21-22), so that even there the signs and wonders of the prophets are not made the criteria of their divine mission.
Israel was to adhere firmly to the Lord its God (cf. Deu 4:4), and to put to death the prophet who preached apostasy from Jehovah, the Redeemer of Israel out of the slave-house of Egypt. להדּיחך, "to force thee from the way in which Jehovah hath commanded thee to walk." The execution of seducers to idolatry is enjoined upon the people, i.e., the whole community, not upon single individuals, but upon the authorities who had to maintain and administer justice. "So shalt thou put the evil away from the midst of thee." הרע is neuter, as we may see from Deu 17:7, as comp. with Deu 13:2. The formula, "so shalt thou put the evil away from the midst of thee," which occurs again in Deu 17:7, Deu 17:12; Deu 19:19; Deu 21:21; Deu 22:21-22, Deu 22:24, and Deu 24:7 (cf. Deu 19:13, and Deu 21:9), belongs to the hortatory character of Deuteronomy, in accordance with which a reason is given for all the commandments, and the observance of them is urged upon the congregation as a holy affair of the heart, which could not be expected in the objective legislation of the earlier books.
The second case was when the temptation to idolatry proceeded from the nearest blood-relations and friends. The clause, "son of thy mother," is not intended to describe the brother as a step-brother, but simply to bring out the closeness of the fraternal relation; like the description of the wife as the wife of thy bosom, who lies in thy bosom, rests upon thy breast (as in Deu 28:54; Mic 7:5), and of the friend as "thy friend which is as thine own soul," i.e., whom thou lovest as much as thy life (cf. Sa1 18:1, Sa1 18:3). בּסּתר belongs to יסית: if the temptation occurred in secret, and therefore the fact might be hidden from others. The power of love and relationship, which flesh and blood find it hard to resist, is placed here in contrast with the supposed higher or divine authority of the seducers. As the persuasion was already very seductive, from the fact that it proceeded from the nearest blood-relations and most intimate friends, and was offered in secret, it might become still more so from the fact that it recommended the worship of a deity that had nothing in common with the forbidden idols of Canaan, and the worship of which, therefore, might appear of less consequence, or commend itself by the charm of peculiarity and novelty. To prevent this deceptive influence of sin, it is expressly added in Deu 13:8 (7), "of the gods nigh unto thee or far off from thee, from the one end of the earth even unto the other end of the earth," i.e., whatever gods there might be upon the whole circuit of the earth.
To such persuasion Israel was not to yield, nor were they to spare the tempters. The accumulation of synonyms (pity, spare, conceal) serves to make the passage more emphatic. כּסּה, to cover, i.e., to keep secret, conceal. They were to put him to death without pity, viz., to stone him (cf. Lev 20:2). That the execution even in this case was to be carried out by the regular authorities, is evident from the words, "thy hand shall be first against him to put him to death, and the hand of all the people afterwards," which presuppose the judicial procedure prescribed in Deu 17:7, that the witnesses were to cast the first stones at the person condemned.
This was to be done, and all Israel was to hear it and fear, that no such wickedness should be performed any more in the congregation. The fear of punishment, which is given here as the ultimate end of the punishment itself, is not to be regarded as the principle lying at the foundation of the law, but simply, as Calvin expresses it, as "the utility and fruit of severity," one reason for carrying out the law, which is not to be confounded with the so-called deterrent theory, i.e., the attempt to deter from crime by the mode of punishing (see my Archologie, ii. p. 262).
The third case is that of a town that had been led away to idolatry. "If thou shalt hear in one of thy cities." בּאחת, not de una, of one, which שׁמע with בּ never can mean, and does not mean even in Job 26:14. The thought is not that they would hear in one city about another, as though one city had the oversight over another; but there is an inversion in the sentence, "if thou hear, that in one of thy cities...worthless men have risen up, and led the inhabitants astray to serve strange gods." לאמר introduces the substance of what is heard, which follows in Deu 13:14. יצא merely signifies to rise up, to go forth. מקּרבּך, out of the midst of the people.
Upon this report the people as a whole, of course through their rulers, were to examine closely into the affair (היטב, an adverb, as in Deu 9:21), whether the word was established as truth, i.e., the thing was founded in truth (cf. Deu 17:4; Deu 22:20); and if it really were so, they were to smite the inhabitants of that town with the edge of the sword (cf. Gen 34:26), putting the town and all that was in it under the ban. "All that is in it" relates to men, cattle, and the material property of the town, and not to men alone (Schultz). The clause from "destroying" to "therein" is a more minute definition of the punishment introduced as a parenthesis; for "the cattle thereof," which follows, is also governed by "thou shalt smite." The ban was to be executed in all its severity as upon an idolatrous city: man and beast were to be put to death without reserves; and its booty, i.e., whatever was to be found in it as booty-all material goods, therefore - were to be heaped together in the market, and burned along with the city itself. ליהוה כּליל (Eng. Ver. "every whit, for the Lord thy God") signifies "as a whole offering for the Lord" (see Lev 6:15-16), i.e., it was to be sanctified to Him entirely by being destroyed. The town was to continue an eternal hill (or heap of ruins), never to be built up again.
To enforce this command still more strongly, it is expressly stated, that of all that was burned, nothing whatever was to cleave or remain hanging to the hand of Israel, that the Lord might turn from His wrath and have compassion upon the nation, i.e., not punish the sin of one town upon the nation as a whole, but have mercy upon it and multiply it, - make up the diminution consequent upon the destruction of the inhabitants of that town, and so fulfil the promise given to the fathers of the multiplication of their seed.
Jehovah would do this if Israel hearkened to His voice, to do what was right in His eyes. In what way the appropriation of property laid under the ban brought the wrath of God upon the whole congregation, is shown by the example of Achan (Josh 7).