(10) Go unto the people, and sanctify them.--The approaching manifestation required, above all things, that the people should be "sanctified." Sanctification is twofold--outward and inward. The real essential preparation for approach to God is inward sanctification; but no external command can secure this. Moses was therefore instructed to issue directions for outward purification; and it was left to the spiritual insight of the people to perceive and recognise that such purity symbolised and required internal purification as its counterpart. The external purification was to consist in three things--(1) Ablution, or washing of the person; (2) washing of clothes; and (3) abstinence from sexual intercourse (Exodus 19:15).

Let them wash their clothes.--The Levitical law required the washing of clothes on many occasions (Leviticus 11:25; Leviticus 11:28; Leviticus 11:40; Leviticus 13:6; Leviticus 13:34; Leviticus 13:58; Leviticus 14:8-9; Leviticus 14:47; Leviticus 15:5-22, &c.) In connection with purification. The same idea prevailed in Egypt (Herod., 2:37), in Greece (Horn. Od., iv. 1. 759), and in Rome (Dollinger, Jew and Gentile, vol. ii., p. 82). It is a natural extension of the idea that ablution of the person cleanses, not from physical only, but from moral defilement.

Verses 10-15. - THE PREPARATION OF THE PEOPLE AND OF THE MOUNTAIN FOR THE MANIFESTATION OF GOD UPON IT. The people having accepted God's terms, the time had come for the revelation in all its fulness of the covenant which God designed to make with them. This, it was essential, they should perceive and know to come from God, and not to be the invention of Moses. God, therefore, was about to manifest himself. But ere he could do this with safety, it was requisite that certain preparations should be made. Before man can be fit to approach God, he needs to be sanctified. The essential sanctification is internal; but, as internal purity and holiness cannot be produced at a given moment, Moses was ordered to require its outward symbol, external bodily cleanliness, by ablution and the washing of clothes, as a preliminary to God's descent upon the mountain (vers. 10, 13). It would be generally understood that this external purity was symbolical only, and needed to be accompanied by internal cleanliness. Further, since even the purest of men is impure in God's sight, and since there would be many in the congregation who had attempted no internal cleansing, it was necessary to provide that they should not draw too near, so as to intrude on the holy ground or on God's presence. Moses was therefore required to have a fence erected round the mountain, between it and the people, and to proclaim the penalty of death against all who should pass it and touch the mount (vers. 12, 13). In executing these orders, Moses gave an additional charge to the heads of families, that they should purify themselves by an act of abstinence which he specified (ver. 15) Verse 10. - Go unto the people. Moses had withdrawn himself from the people to report their words to God (vers. 8, 9). He was now commanded to return to them. Sanctify them. Or "purify them." Purification in Egypt was partly by washing, partly, by shaving the hair, either front the head only, or from the entire body (Herod. 2:37), partly perhaps by other rites. The Israelites seem ordinarily to have purified themselves by washing only. To-day and to-morrow. The fourth and fifth of Sivan, according to the Jewish tradition, the Decalogue having been given upon the sixth. The requirement of a two-days' preparation marked the extreme sanctity of the occasion. Let them wash their clothes. Compare Leviticus 15:5. Rich people could "change their garments" on a sacred occasion (Genesis 35:2); the poorer sort, having no change, could only wash them.

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 the Lord said unto Moses,.... On the fourth day, according to the Targum of Jonathan:

go unto the people; go down from the mountain, from the top of it, where he now was, to the camp of Israel, which was pitched before it:

and sanctify them today and tomorrow; the fourth and fifth days of the month; that is, he was, to instruct them how they were to sanctify themselves in an external way, by washing themselves, as after mentioned, their bodies and clothes, and by abstaining from all sensual pleasures, lawful or unlawful:

and let them wash their clothes; which the Jews understood not of their garments, but of their bodies also; teaching them by these outward things the necessity of internal purity and holiness, to appear before God: these outward rites were in use before the law of Moses, as appears from Genesis 35:2 and the Heathens themselves have similar notions of the cleanness of bodies and garments, as well as the purity of mind, being acceptable to their deities (n).

(n) "Casta placent superis, pura cum veste venito". Tibullus.