(12) Thou shalt set bounds.--Here was another formal and mechanical direction, having for its object to deepen and intensify the lesson of God's unapproachable majesty and holiness. Moses was required to "set bounds to the people," i.e., to make a substantial fence between the camp and the base of Sinai, which should prevent both animals and men from coming in contact with the mountain. Modern travellers generally observe how abruptly the rocky precipice of Ras Sufsafeh rises from the plain in front of it, so that in many places it is quite possible to stand on the plain and yet touch the mountain. The idea that a line of natural mounds now to be seen near the base of Sinai represents the "bounds" of Moses (Stanley, Sinai and Palestine, p. 43) is unsatisfactory, since the "bounds" of Moses were most certainly artificial ones. It is, however, possible that his "bounds" may have followed the line of the natural barrier.

That ye go not up into the mount.--Unless it had been forbidden, there might have seemed to be no reason why pious Israelites might not have ascended the height, to draw near to God in prayer. It is a praiseworthy feeling which breathes in the words, "Nearer, my God, to thee;" but the nation was not fit for close approach.

Verse 12. - Thou shalt set bounds. The erection of a fence or barrier, between the camp and the mountain - not necessarily all round the mountain - seems to be meant. This barrier may have run along the line of low alluvial mounds at the foot of the cliff of Ras Sufsafeh, mentioned by Dean Stanley (Sinai and Palestine, p. 43), but cannot have been identical with them, since it was an artificial fence. That ye go not up into the mount. Curiosity might have tempted some to ascend the mount, if it had not been positively forbidden under the penalty of death; carelessness might have brought many into contact with it, since the cliff rises abruptly from the plain. Unless the fence had been made, cattle would, naturally, have grazed along its base. To impress the Israelites with a due sense of the awful majesty of God, and the sacredness of everything material that it brought into close relations with him, the mount itself was declared holy - none but Moses and Aaron might go up into it; none might touch it; even the stray beast that approached it must suffer death for its unwitting offence (ver. 13). Whosoever toucheth the mount. The mountain may be "touched" from the plain - it rises so abruptly. Shall be surely put to death. A terrible punishment, and one which, to modern ideas, seems excessive. But it was only by terrible threats, and in some cases by terrible punishments (2 Samuel 6:7), that the Israelites could be taught reverence. A profound reverence lies at the root of all true religious feeling; and for the education of the world, it was requisite, in the early ages, to inculcate the necessity of this frame of mind in some very marked and striking way.

19:9-15 The solemn manner in which the law was delivered, was to impress the people with a right sense of the Divine majesty. Also to convince them of their own guilt, and to show that they could not stand in judgment before God by their own obedience. In the law, the sinner discovers what he ought to be, what he is, and what he wants. There he learns the nature, necessity, and glory of redemption, and of being made holy. Having been taught to flee to Christ, and to love him, the law is the rule of his obedience and faith.And thou shall set bounds to the people round about,.... That is, round about the mountain, by drawing a line, throwing up a foss or ditch, or else by laying up heaps of stones or sand, which might be come at easily, or bushes and branches of trees, which grew thick on the mount, from whence it had its name; but be it what will that were used, these were to signify, that so far the people might go, but no further, which their curiosity might prompt them to:

saying, take heed unto yourselves that ye go not up into the mount; so far were they from being allowed to go up to the top of it, that they were not allowed to ascend it at all, or to go any further than where the ascent or rise began; it was at their peril to ascend, and this was what they were to take heed unto, lest they incurred danger:

or touch the border of it; it being the mountain of God, and relatively holy through his presence on it:

whosoever toucheth the mount shall be surely put to death; which severe law was made to deter them from any attempt to go up the mountain, since it was death even to touch it, see Hebrews 12:18.