From Matthew Henry’s Commentary on the Book of Leviticus, Chapter 19, verse 3:
“That children be obedient to their parents: “You shall fear every man his mother and his father, v. 3. 1. The fear here required is the same with the honour commanded by the fifth commandment; see Mal. i. 6. It includes inward reverence and esteem, outward expressions of respect, obedience to the lawful commands of parents, care and endeavour to please them and make them easy, and to avoid every thing that may offend and grieve them, and incur their displeasure. The Jewish doctors ask, “What is this fear that is owing to a father?” And they answer, “It is not to stand in his way nor to sit in his place, not to contradict what he says nor to carp at it, not to call him by his name, either living or dead, but ‘My Father,’ or ‘Sir;’ it is to provide for him if he be poor, and the like.” 2. Children, when they grow up to be men, must not think themselves discharged from this duty: every man, though he be a wise man, and a great man, yet must reverence his parents, because they are his parents. 3. The mother is put first, which is not usual, to show that the duty is equally owing to both; if the mother survive the father, still she must be reverenced and obeyed. 4. It is added, and keep my sabbaths. If God provides by his law for the preserving of the honour of parents, parents must use their authority over their children for the preserving of the honour of God, particularly the honour of his sabbaths, the custody of which is very much committed to parents by the fourth commandment, Thou, and thy son, and thy daughter. The ruin of young people has often been observed to begin in the contempt of their parents and the profanation of the sabbath day. Fitly therefore are these two precepts here put together in the beginning of this abridgment of the statutes: “You shall fear, every man, his mother and his father, and keep my sabbaths. Those are hopeful children, and likely to do well, that make conscience of honouring their parents and keeping holy the sabbath day. 5. The reason added to both these precepts is, “I am the Lord your God; the Lord of the sabbath and the God of your parents.”
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From John Calvin’s Commentary on Leviticus 18:5:
“You shall therefore keep My statutes and My judgments, which if a man does, he shall live by them: I am the LORD.”
Ye shall therefore keep my statutes. Although Moses introduces this passage, where he exhorts the Israelites to cultivate chastity in respect to marriage, and not to fall into the incestuous pollutions of the Gentiles, yet, as it is a remarkable one, and contains general instruction, from whence Paul derives his definition of the righteousness of the Law, (Romans 10:5,) it seems to me to come in very appropriately here, inasmuch as it sanctions and confirms the Law by the promise of reward. The hope of eternal life is, therefore, given to all who keep the Law; for those who expound the passage as referring to this earthly and transitory life are mistaken. The cause of this error was, because they feared that thus the righteousness of faith might be subverted, and salvation grounded on the merit of works. But Scripture does not therefore deny that men are justified by works, because the Law itself is imperfect, or does not give instructions for perfect righteousness; but because the promise is made of none effect by our corruption and sin. Paul, therefore, as I have just said, when he teaches that righteousness is to be sought for in the grace of Christ by faith, (Romans 10:4,) proves his statement by this argument, that none is justified who has not fulfilled what the Law commands. Elsewhere also he reasons by contrast, where he contends that the Law does not accord with faith as regards the cause of justification, because the Law requires works for the attainment of salvation, whilst faith directs us to Christ, that we may be delivered from the curse of the Law. Foolishly, then, do some reject as an absurdity the statement, that if a man fulfills the Law he attains to righteousness; for the defect does not arise from the doctrine of the Law, but from the infirmity of men, as is plain from another testimony given by Paul. (Romans 8:3.) We must observe, however, that salvation is not to be expected from the Law unless its precepts be in every respect complied with; for life is not promised to one who shall have done this thing, or that thing, but, by the plural word, full obedience is required of us. The pratings of the Popish theologians about partial righteousness are frivolous and silly, since God embraces at once all the commandments; and who is there that can boast of having thoroughly fulfilled them? If, then, none was ever clear of transgression, or ever will be, although God by no means deceives us, yet the promise becomes ineffectual, because we do not perform our part of the agreement.
I love getting in arguments with people who know only how to parrot what they have been taught. (not for prideful reasons). The most recent one has been the good old Marcionite heresy that has envolped much of Liberationist, Liberal, and Pentecostal/Broad Evangelical theology that pits Jesus (the “god” of the New Testament) vs. YHWH (the “god” of the Old Testament). It never ceases to amaze me how grumpy people get when you show them the obvious. In this case we have Jesus and the “love your neighbor as yourself” passage. Many will point to this passage in an attempt to show the supposed difference between the OT Ethic of “eye for an eye” and the NT Ethic of “Love your enemy.” Whereas when you simply point out to them Duet 6:1-9 and Lev 19:18 and show them Jesus was merely reminding us of what the Law already taught. What this attempted argument really shows is that people just plain old do not know their Bibles.
You will here some say in the Reformed world that the Mosaic Administration is a republication of the Covenant of Works, citing most effectively Leviticus 18:5 (“So you shall keep My statutes and My judgments, by which a man may live if he does them; I am the LORD.”) and other places where it seems that obedience to the Law as given by Moses is the requirement for the Lord’s blessing and therefore life. However I believe that one can cite the same verses and make the opposite notation, that the Law being an administration of the Second Covenant, the Covenant of Grace, is not a Covenant of Works because most strikingly that which a Covenant of Works is cannot be fulfilled by the Mosaic Covenant. So there is I think a definitional mistake by categorizing the Mosaic administration in any part of a Covenant of Works because in doing so it presupposes that one can follow the Law to receive salvation like Adam (even if such a thing were possible, which it is not), who was first under the Covenant of Works for salvation and failed. Since Adam failed the probationary test we cannot now fulfill the requirements of this covenant and since according to Romans 5 the curse of this failure continues in us since Adam was our covenantal head it would therefore not make sense that God would put is again under a covenant which had been broken by Adam’s disobedience (and our disobedience in Adam). Especially since we continue under its curse. The Covenant of Works had already been abrogated, why would/should it be instituted again by the Mosaic administration since we who are descendants of Adam were already condemned? It seems to be unnecessary to put us again under condemnation a second time.
The Westminster Confession of Faith Chapter 7, sections III, IV, & V makes clear that the Law (or Mosaic covenant) is an administration of the Covenant of Grace.
Chapter 7 –
Of God’s Covenant with Man.
III. Man by [Adam’s] fall having made himself incapable of life by that covenant, the Lord was pleased to make a second, commonly called the covenant of grace: wherein he freely offered unto sinners life and salvation by Jesus Christ, requiring of them faith in him, that they may be saved, and promising to give unto all those that are ordained unto life, his Holy Spirit, to make them willing and able to believe.
IV. This covenant of grace is frequently set forth in the Scripture by the name of a testament, in reference to the death of Jesus Christ, the testator, and to the everlasting inheritance, with all things belonging to it, therein bequeathed.
V. This covenant was differently administered in the time of the law, and in the time of the gospel: under the law it was administered by promises, prophecies, sacrifices, circumcision, the paschal lamb, and other types and ordinances delivered to the people of the Jews, all fore-signifying Christ to come, which were for that time sufficient and efficacious, through the operation of the Spirit, to instruct and build up the elect in faith in the promised Messiah, by whom they had full remission of sins, and eternal salvation, and is called the Old Testament.
You see in section V that the Divines at least believed the Law (thereby meaning the Mosaic Covenant) is just a special administration of the Covenant of Grace. While administered differently than “in the time of the gospel” it still is part of the Second Covenant, or the Covenant of Grace.