Neither shalt thou go up. When God had prescribed modesty to the priests in their whole life, and in their private actions, no wonder that He should require especial care of decency and propriety in the performance of their sacred duties. He had indeed already desired that the priests should wear drawers or breeches when they went into the sanctuary; yet not content with this symbol of purity, He forbids them to ascend the altar by steps, lest haply the drawers themselves should be seen; since the dignity and sanctity of sacred things would thus be impaired. By all means, therefore, He would induce the Israelites to conduct themselves most purely and most chastely in the exercises of religion.

Neither shalt thou go up by steps unto mine altar - The word altar comes from altus, high or elevated, though the Hebrew word מזבח mizbach, from זבח zabach, to slay, kill, etc., signifies merely a place for sacrifice; see Genesis 8:20. But the heathens, who imitated the rites of the true God in their idolatrous worship, made their altars very high; whence they derived their name altaria, altars, i.e., very high or elevated places; which they built thus, partly through pride and vain glory, and partly that their gods might the better hear them. Hence also the high places or idolatrous altars so often and so severely condemned in the Holy Scriptures. The heathens made some of their altars excessively high; and some imagine that the pyramids were altars of this kind, and that the inspired writer refers to those in these prohibitions. God therefore ordered his altars to be made,
1. either of simple turf, that there might be no unnecessary expense, which, in their present circumstances, the people could not well afford; and that they might be no incentives to idolatry from their costly or curious structure; or
2. of unhewn stone, that no images of animals or of the celestial bodies might be sculptured on them, as was the case among the idolaters, and especially among the Egyptians, as several of their ancient altars which remain to the present day amply testify; which altars themselves, and the images carved on them, became in process of time incentives to idolatry, and even objects of worship.
In short, God formed every part of his worship so that every thing belonging to it might be as dissimilar as possible from that of the surrounding heathenish nations, and especially the Egyptians, from whose land they had just now departed. This seems to have been the whole design of those statutes on which many commentators have written so largely and learnedly, imagining difficulties where probably there are none. The altars of the tabernacle were of a different kind.
In this and the preceding chapter we have met with some of the most awful displays of the Divine Majesty; manifestations of justice and holiness which have no parallel, and can have none till that day arrive in which he shall appear in his glory, to judge the quick and the dead. The glory was truly terrible, and to the children of Israel insufferable; and yet how highly privileged to have God himself speaking to them from the midst of the fire, giving them statutes and judgments so righteous, so pure, so holy, and so truly excellent in their operation and their end, that they have been the admiration of all the wise and upright in all countries and ages of the world, where their voice has been heard! Mohammed defied all the poets and literati of Arabia to match the language of the Koran; and for purity, elegance, and dignity it bore away the palm, and remained unrivaled. This indeed was the only advantage which the work derived from its author; for its other excellences it was indebted to Moses and the prophets, to Christ and the apostles; as there is scarcely a pure, consistent, theological notion in it, that has not been borrowed from our sacred books. Moses calls the attention of the people, not to the language in which these Divine laws were given, though that is all that it should be, and every way worthy of its author; compressed yet perspicuous; simple yet dignified; in short, such as God should speak if he wished his creatures to comprehend; but he calls their attention to the purity, righteousness, and usefulness of the grand revelation which they had just received. For what nation, says he, is there so great, who hath God so nigh unto them, as Jehovah our God is, in all things that we call upon him for? And what nation hath statutes and judgments so righteous as all this law which I set before you this day? And that which was the sum of all excellence in the present case was this, that the God who gave these laws dwelt among his people; to him they had continual access, and from him received that power without which obedience so extensive and so holy would have been impossible; and yet not one of these laws exacted more than eternal reason, the nature and fitness of things, the prosperity of the community, and the peace and happiness of the individual, required. The Law is holy, and the Commandment is Holy, Just, and Good.
To show still more clearly the excellence and great utility of the ten commandments, and to correct some mistaken notions concerning them, it may be necessary to make a few additional observations. And
1. It is worthy of remark that there is none of these commandments, nor any part of one, which can fairly be considered as merely ceremonial. All are moral, and consequently of everlasting obligation.
2. When considered merely as to the letter, there is certainly no difficulty in the moral obedience required to them. Let every reader take them up one by one, and ask his conscience before God, which of them he is under a fatal and uncontrollable necessity to break?
3. Though by the incarnation and death of Christ all the ceremonial law which referred to him and his sacrifice is necessarily abrogated, yet, as none of these ten commandments refer to any thing properly ceremonial, therefore they are not abrogated.
4. Though Christ came into the world to redeem them who believe from the curse of the law, he did not redeem them from the necessity of walking in that newness of life which these commandments so strongly inculcate.
5. Though Christ is said to have fulfilled the law for us, yet it is nowhere intimated in the Scripture that he has so fulfilled these Ten Laws, as to exempt us from the necessity and privilege of being no idolaters, swearers, Sabbath-breakers, disobedient and cruel children, murderers, adulterers, thieves, and corrupt witnesses. All these commandments, it is true, he punctually fulfilled himself; and all these he writes on the heart of every soul redeemed by his blood.
6. Do not those who scruple not to insinuate that the proper observation of these laws is impossible in this life, and that every man since the fall does daily break them in thought, word, and deed, bear false witness against God and his truth? and do they not greatly err, not knowing the Scripture, which teaches the necessity of such obedience, nor the power of God, by which the evil principle of the heart is destroyed, and the law of purity written on the soul? If even the regenerate man, as some have unwarily asserted, does daily break these commands, these ten words, in thought, word, and deed, he may be as bad as Satan for aught we know; for Satan himself cannot transgress in more forms than these, for sin can be committed in no other way, either by bodied or disembodied spirits, than by thought, or word, or deed. Such sayings as these tend to destroy the distinction between good and evil, and leave the infidel and the believer on a par as to their moral state. The people of God should be careful how they use them.
7. It must be granted, and indeed has sufficiently appeared from the preceding exposition of these commandments, that they are not only to be understood in the letter but also in the spirit, and that therefore they may be broken in the heart while outwardly kept inviolate; yet this does not prove that a soul influenced by the grace and spirit of Christ cannot most conscientiously observe them; for the grace of the Gospel not on)y saves a man from outward but also from inward sin; for, says the heavenly messenger, his name shall be called Jesus, (i.e., Savior), because he shall save, (i.e., Deliver) his people From their sins. Therefore the weakness or corruption of human nature forms no argument here, because the blood of Christ cleanses from all unrighteousness; and he saves to the uttermost all who come unto the Father through him. It is therefore readily granted that no man unassisted and uninfluenced by the grace of Christ can keep these commandments, either in the letter or in the spirit; but he who is truly converted to God, and has Christ dwelling in his heart by faith, can, in the letter and in the spirit, do all these things, Because Christ Strengthens him - Reader, the following is a good prayer, and oftentimes thou hast said it; now learn to pray it: "Lord, have mercy upon us, and incline our hearts to keep these laws! Lord, have mercy upon us, and write all these thy laws in our hearts, we beseech thee!" - Com. Service.

Neither shalt thou go up by steps unto mine altar, that thy (p) nakedness be not discovered thereon.
(p) Which might be by his stooping or flying up of his clothes.

Neither shalt thou go up by steps unto mine altar,.... That is, you priests, the sons of Aaron, as the Targums of Jonathan and Jerusalem paraphrase the words; the altar of burnt offering built when the tabernacle was seemed not to require any, being but three cubits high, Exodus 27:1 but that in Solomon's temple did, being ten cubits high, 2-Chronicles 4:1 and therefore some method must be used to ascend it, and do the business that was to be done on it: now the Jews say (b), there was what they call "Kibbesh", a sort of a causeway made of earth thrown up, which rose gradually and led to the top of the altar, and was about thirty two cubits long and sixteen broad: and so the Targum of Jonathan paraphrases the words,"thou shalt not go up by steps to mine altar, but by bridges;''express mention is made of stairs to the altar in Ezekiel's vision, Ezekiel 43:17.
that thy nakedness be not discovered thereon; that part of the body which is not to be named, and ought not to be seen, and which would be exposed if there were many steps, and these at a distance from each other; which would oblige them to take large strides, and so be in danger of discovering those parts which would make them the object of contempt and ridicule with the people; since as yet breeches were not used, and the garments were long loose ones, which were easily turned aside, or the parts under them seen by those below; to prevent which, afterwards linen breeches were ordered to be made for the priests, and to be used by them in their service: Maimonides (c) thinks the reason of this was, because formerly the idolatrous worship of Peor was performed by uncovering of their nakedness before it; and so by this is expressed God's detestation of such an impure and abominable practice; but this is uncertain; however, this we may be sure of, that this is the will of God, that all immodesty and indecency, and whatever tends to create impure thoughts and stir up unclean lusts, should be carefully avoided in his worship.
(b) Middot, c. 3. sect. 3. (c) Ut supra. (Apud L'Empereur in Middot, ib.)

by steps--a precaution taken for the sake of decency, in consequence of the loose, wide, flowing garments of the priests.

Neither shall thou go at by steps unto mine altar - Indeed afterwards God appointed an altar ten cubits high. But it is probable, they went not up to that by steps, but by a sloping ascent.