Exodus 19:10

Sanctify them. The Lord was about to proclaim His holy law in person, in order to remove all suspicion that Moses had anything whatever to do with its composition. Their appearance in the presence of God would require sanctification, without which none can see Him (Heb. 12:14). Sanctification is essentially a matter of the spirit, of being “pure in heart” (Matt. 5:8). The outward acts of preparation were designed to impress upon the people the need of preparing their hearts to meet God (1 Thess. 5:23; 1 John 3:3). Though to the Egyptians purification meant washing the body, including also shaving the hair from the head, and sometimes from the entire body, the Israelites seem to have purified themselves by washing only.

Holiness is to be considered seriously each time we approach God. The unholy will not be rejected by Him if they come in repentance, accepting the grace of Christ. He accepts the sinner that He may make him holy, and thus qualify him for fellowship with God (Eph. 1:4; 5:25-27; Titus 2:11-14). Since the law that was soon to be given is an expression of God’s holiness, it was only fitting that the people prepare to receive it by sanctifying themselves. If the Israelites were to be the people of God, it was imperative that they appreciate the sacredness of this relationship. Therefore we can understand why God made the giving of His holy law an occasion to impress the people, deeply and dramatically, with the conviction of its sanctity and importance. This was particularly necessary since the Hebrews, oppressed by their Egyptian masters, had to a great extent lost a knowledge of the character and majesty of God.

To day and to morrow. According to Jewish tradition this would be the fourth and fifth of the month Sivan, the Decalogue being given on the sixth. The two days’ preparation was to lend emphasis to the sanctity of the event.

Wash. The rich might change their clothes when occasion required, but the people, in general, the poorer classes, having no change of garments, must wash those they wore (Lev. 15:5).