Leviticus 19 is generally viewed today as forming the theological center of the latter portion of the legal codes of Leviticus. And the substance of this center, as most readers of the text agree, is the call to holiness: “Say to all the congregation of the people of Israel, You shall be holy; for I the Lord your God am holy” (19:2).
Obviously, holiness is a crucial reality for Leviticus as a whole, but as the purposively directing theological principle for the entire book, or at least for that textual core known as the Holiness Code, it is only now in Lev. 19 that many commentators see its full force as being unveiled.
And that force has generally been evaluated in terms of the overwhelming power of moral purity. . . . Holiness is less a quality or character attributed to God—and reflected in creatures—than it is a description of how God in fact temporally wills to act with respect to his creation, by coming to it with his whole being.
Leviticus 19:2 takes what almost seemed a passing divine exhortation in 11:44—“be holy, for I am holy”—and turns it into the summary description of the entire ethical law of the book: “You shall be holy, for I the Lord your God am holy.”
As commentators note, God asks Moses to speak these injunctions “to all the congregation of the people of Israel,” an audience traditionally seen here as gathered together in one large group, addressed directly and without mediation, requiring a miracle of vocal projection from the otherwise halting Moses. They are thus called as a people to the core of their vocation (compare Exod. 19:6 and 1 Pet. 2:9).
What could be more central, therefore, than this opening directive toward holiness?