Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
As Theologians are divided on the question whether the actions of God are the result of His wisdom, or only of His will without being intended for any purpose whatever, so they are also divided as regards the object of the commandments which God gave us. Some of them hold that the commandments have no object at all; and are only dictated by the win of God. Others are of opinion that all commandments and prohibitions are dictated by His wisdom and serve a certain aim; consequently there is a reason for each one of the precepts: they are enjoined because they are useful. All of us, the common people as well as the scholars, believe that there is a reason for every precept, although there are commandments the reason of which is unknown to us, and in which the ways of God's wisdom are incomprehensible. This view is distinctly expressed in Scripture; comp. "righteous statutes and judgments" (Deut. iv. 8); "the judgments of the Lord are true, and righteous altogether" (Ps. xix. 10). There are commandments which are called ḥuḳḳim, "ordinances," like the prohibition of wearing garments of wool and linen (sha‘atnez), boiling meat and milk together, and the sending of the goat [into the wilderness on the Day of Atonement]. Our Sages use in reference to them phrases like the following: "These are things which I have fully ordained for thee: and you dare not criticize them"; "Your evil inclination is turned against them"; and "non-Jews find them strange." But our Sages generally do not think that such precepts have no cause whatever, and serve no purpose; for this would lead us to assume that God's actions are purposeless. On the contrary, they hold that even these ordinances have a cause, and are certainly intended for some use, although it is not known to us; owing either to the deficiency of our knowledge or the weakness of our intellect. Consequently there is a cause for every commandment: every positive or negative precept serves a useful object; in some cases the usefulness is evident, e.g., the prohibition of murder and theft; in others the usefulness is not so evident, e.g., the prohibition of enjoying the fruit of a tree in the first three years (Lev. xix. 73), or of a vineyard in which other seeds have been growing (Deut. xxii. 9). Those commandments, whose object is generally evident, are called "judgments" (mishpatim); those whose object is not generally clear are called "ordinances" (ḥuḳḳim). Thus they say [in reference to the words of Moses]: Ki lo dabar rek hu mi-kem (lit." for it is not a vain thing for you, "Deut. xxxii. 74); "It is not in vain, and if it is in vain, it is only so through you." That is to say, the giving of these commandments is not a vain thing and without any useful object; and if it appears so to you in any commandment, it is owing to the deficiency in your comprehension. You certainly know the famous saying that Solomon knew the reason for all commandments except that of the "red heifer." Our Sages also said that God concealed
the causes of commandments, lest people should despise them, as Solomon did in respect to three commandments, the reason for which is clearly stated. In this sense they always speak; and Scriptural texts support the idea. I have, however, found one utterance made by them in Bereshit-rabba (sect. xliv.), which might at first sight appear to imply that some commandments have no other reason but the fact that they are commanded, that no other object is intended by them, and that they do not serve any useful object I mean the following passage: What difference does it make to God whether a beast is killed by cutting the neck in front or in the back? Surely the commandments are only intended as a means of trying man; in accordance with the verse, "The word of God is a test" (lit. tried) (Ps. xviii. 31). Although this passage is very strange, and has no parallel in the writings of our Sages, I explain it, as you shall soon hear, in such a manner that I remain in accord with the meaning of their words and do not depart from the principle which we agreed upon, that the commandments serve a useful object; "for it is not a vain thing for you"; "I have not said to the seed of Jacob, seek me in vain. I the Lord speak righteousness, declare that which is right" (Isa. xlv. 19). I will now tell you what intelligent persons ought to believe in this respect; namely, that each commandment has necessarily a cause, as far as its general character is concerned, and serves a certain object; but as regards its details we hold that it has no ulterior object. Thus killing animals for the purpose of obtaining good food is certainly useful, as we intend to show (below, ch. xlviii.); that, however, the killing should not be performed by neḥirah (poleaxing the animal), but by sheḥitah (cutting the neck), and by dividing the œsophagus and the windpipe in a certain place; these regulations and the like are nothing but tests for man's obedience. In this sense you will understand the example quoted by our Sages [that there is no difference] between killing the animal by cutting its neck in front and cutting it in the back. I give this instance only because it has been mentioned by our Sages; but in reality [there is some reason for these regulations]. For as it has become necessary to eat the flesh of animals, it was intended by the above regulations to ensure an easy death and to effect it by suitable means; whilst decapitation requires a sword or a similar instrument, the sheḥitah can be performed with any instrument; and in order to ensure an easy death our Sages insisted that the knife should be well sharpened.
A more suitable instance can be cited from the detailed commandments concerning sacrifices. The law that sacrifices should be brought is evidently of great use, as will be shown by us (infra, chap. xlvi.); but we cannot say why one offering should be a lamb, whilst another is a ram; and why a fixed number of them should be brought. Those who trouble themselves to find a cause for any of these detailed rules, are in my eyes void of sense: they do not remove any difficulties, but rather increase them. Those who believe that these detailed rules originate in a certain cause, are as far from the truth as those who assume that the whole law is useless. You must know that Divine Wisdom demanded it--or, if you prefer, say that circumstances made it necessary--that there should be parts [of His work] which have no certain object: and as regards the Law, it appears to be impossible that it should not include some matter of this kind. That it cannot be avoided
may be seen from the following instance. You ask why must a lamb be sacrificed and not a ram? but the same question would be asked, why a ram had been commanded instead of a lamb, so long as one particular kind is required. The same is to be said as to the question why were seven lambs sacrificed and not eight; the same question might have been asked if there were eight, ten, or twenty lambs, so long as some definite number of lambs were sacrificed. It is almost similar to the nature of a thing which can receive different forms, but actually receives one of them. We must not ask why it has this form and not another which is likewise possible, because we should have to ask the same question if instead of its actual form the thing had any of the other possible forms. Note this, and understand it. The repeated assertion of our Sages that there are reasons for all commandments, and the tradition that Solomon knew them, refer to the general purpose of the commandments, and not to the object of every detail. This being the case, I find it convenient to divide the six hundred and thirteen precepts into classes: each class will include many precepts of the same kind, or related to each other by their character. I will [first] explain the reason of each class, and show its undoubted and undisputed object, and then I shall discuss each commandment in the class, and expound its reason. Only very few will be left unexplained, the reason for which I have been unable to trace unto this day. I have also been able to comprehend in some cases even the object of many of the conditions and details as far as these can be discovered. You will hear all this later on. But in order to fully explain these reasons I must premise several chapters; in these I will discuss principles which form the basis of my theory. I will now begin these chapters.