(Excerpt from No Other Standard: Theonomy and its Critics)
A recurring argument against the theonomic view of the Mosaic penal sanctions holds that modern states are restricted to the Noahic covenant in gaining civil laws or penalties from the Old Testament. In this way many critics hope to be able to presume that the Mosaic penal code has now been abrogated, and yet to maintain the validity of the death penalty for murder, since it was stipulated prior to Moses, deals with the image of God, and has not been invalidated by the New Testament. This line of reasoning is overburdened with arbitrariness, false assumptions and fallacious inferences (many of which were rehearsed in Theonomy, pp. 458-466, and which critics have yet to answer).
By endorsing and restricting modern states to the penal justice of the Noahic revelation, do critics also insist on the (equally Noahic) prohibition on eating meat in its blood (Genesis 9:4)? On what basis is this dietary restriction ignored, while capital punishment for murder is endorsed? If pre-Mosaic stipulations are as such universal and perpetual in their validity, the dietary requirement should not be set aside. On the other hand, if only pre-Mosaic stipulations are universal and perpetual standards for modern states, it would seem that we must rule out the state’s right to tax its citizens (which is not mentioned in the Noahic covenant, although countenanced by Paul in Romans 13:6-7). Moreover, if the non-Noahic provisions of the Mosaic civil code are really no longer valid today, then non-theonomists would be compelled to set aside the distinction between manslaughter and pre-meditated murder which is revealed by Moses, but absent from the Noahic covenant. If states today are limited to punishing infractions as defined by the Noahic revelation, there would be precious little protection left to citizens – against such common crimes as theft, fraud, rape, kidnapping, perjury, violation of contracts, compensation for damages, etc.
The fact is that theonomic critics are anything but clear and consistent in their restriction of contemporary social justice to the Noahic revelation. They utilize the Noahic covenant like a convenient taxi, to be enlisted when desired but dismissed at whim. They submit to the Noahic covenant in only a selective fashion, respect the civil restriction to the Noahic covenant in only a selective way, and reject the post-Noahic regulations of the Mosaic law only in a selective way. Such arbitrariness is unacceptable for a theological foundation. Such selectivity is especially disapprobated by the words of our Lord in Matthew 5:17-19, who did not restrict Himself to the validity of the Noahic revelation, but endorsed every jot and tittle of the entire Law and Prophets.
The New Testament no more abrogates the Mosaic covenant’s moral content than it does the Noahic covenant’s moral content. This distinction is invented by theologians to suit preconceived conclusions. To suggest that in contrast to the penal sanctions of the Mosaic covenant, the penal sanction of the Noahic covenant was an expression of common grace, is to invite very mischievous theological inferences. Does this suggest that the Mosaic law regarding crime and punishment was not common (cf. Deut. 4:6-8; Heb. 2:2), was not gracious (cf. Ps. 119:29; Rom. 13:4 with 1 Tim. 1:8-10), or was not an expression of common grace but rather “saving grace”? To suggest that the universality of the Noahic covenant (made with all mankind through Noah) – in contrast to the particularity of the Mosaic covenant (made with
through Moses) – is the theological basis for applying it to the state, is both unbiblical (the Mosaic law was for the whole world as well: e.g., Rom. ) and arbitrarily followed. To be consistent, those who argue in this fashion should also maintain that the only standards of personal morality which are to be applied to mankind today (from the Old Testament anyway) are those of the universal Noahic covenant, not those of the particularistic Mosaic covenant – not even the ten commandments, the love commandments, the prohibition of blasphemy, rape and bestiality, the demand for fair treatment of workers and compassionate treatment of the handicapped, the requirement of just weights and measures, or honoring one’s parents, etc. Israel
Greg L. Bahnsen, No Other Standard: Theonomy and its Critics (Tyler, TX: Institute for Christian Economics, 1991), 218-220. Available for free download at I.C.E. Freebooks.
 With minor variations we find this line of thought set forth by Henry, “The Christian and Political Duty,” God, Revelation and Authority, vol. 6, p. 447; Raymond O. Zorn, “Theonomy in Christian Ethics," Vox Reformata (May, 1982), pp. 17-18; O. Palmer Robertson, Tapes: “Analysis of Theonomy” (available from Mt. Olive Tape Library, Box 42, Mt. Olive, MS 39119), tape# OR1O7A1, A2, B3; H. Wayne House and Thomas Ice, Dominion Theology Blessing or Curse? (Portland, Oregon Multnomah Press, 1988), pp. 86, 119, 127, 130, 135, 137, 339.