(Ex 19, 21-25) Who approach the LORD must sanctify
[21] Then the LORD told Moses, "Go down and warn the people not to break through toward the LORD in order to see him; otherwise many of them will be struck down. [22] The priests, too, who approach the LORD must sanctify themselves; else he will vent his anger upon them." [23] Moses said to the LORD, "The people cannot go up to Mount Sinai, for you yourself warned us to set limits around the mountain to make it sacred." [24] The LORD repeated, "Go down now! Then come up again along with Aaron. But the priests and the people must not break through to come up to the LORD; else he will vent his anger upon them." [25] So Moses went down to the people and told them this.
(CCC 708) This divine pedagogy appears especially in the gift of the Law (Cf. Ex 19- 20; Deut 1-11; 29-30). God gave the Law as a "pedagogue" to lead his people towards Christ (Gal 3:24). But the Law's powerlessness to save man deprived of the divine "likeness," along with the growing awareness of sin that it imparts (Cf. Rom 3:20), enkindles a desire for the Holy Spirit. The lamentations of the Psalms bear witness to this.
