The Foundational Concept of Holiness in Leviticus
The Book of Leviticus is grounded in the truth that God is holy. The word (qodesh) occurs 152 times in the Hebrew text of Leviticus. To say that God is holy means that he is completely separate from all evil or defect. Or to put it in another way, God is completely and perfectly good. The Lord is worthy of total allegiance, exclusive worship, and loving obedience.
In the fallen world, remaining holy requires separation from the evil all around. In 132 instances in Leviticus, God separates himself from things that are evil or “unclean.” Moreover, Israel belongs to the Lord because he has separated them from all other nations and made them holy (Lev. 20:26; 21:8). Israel’s identity arises because by God’s actions they are holy, yet also because the Lord expects Israel to act holy in very practical ways. Israel is called to be holy because the Lord himself is holy (Lev. 11:44, 45; 19:2; 20:7; 21:8). The seemingly disparate laws of Leviticus that deal with the ritual, ethical, commercial, and penal aspects of life all rest on this core notion of holiness.
Just as God’s character remains constantly good, his call for us as his people to be holy is still relevant. Alexander Hill grounds his discussion of Christian business ethics on God’s holiness, justice and love. “A business act is ethical if it reflects God’s holy-just-loving character.” Hill claims that Christians in business reflect divine holiness when they have zeal for God who is their ultimate priority, and who then behave with purity, accountability and humility. These, rather than trying to reproduce the commercial code designed for an agrarian society, are what it means to put Leviticus into practice today. This does not mean ignoring the specifics of the Law, but discerning how God is guiding us to fulfill it in today’s context.
Israel’s outward practice of holiness had two spheres of expression. First, God told the people of Israel to practice holiness with one another according to a comprehensive and complex system of regulations. The anthropologist Mary Douglas has shown, for example, that the food laws in Leviticus were neither arbitrary nor primarily based on what is healthy for people. Israel’s daily diet served as a powerful reminder and reinforcement of God’s holiness, in the sense of being set apart. This was fundamental to Israel’s identity as a distinctive people. Christians understand that on the cross, Jesus abolished the distinction between Jews and Gentiles (Ephesians 2:14–16), so that all his disciples could become holy. As Christopher J. H. Wright pointed out, “So since there is no longer any distinction between Jew and Gentile in Christ, there is no longer any need as far as Christians are concerned for the tangible food distinctions that symbolized it.”  The same is true of the laws against mating different kinds of animals, mixing different seeds in the same field, and wearing clothes of dissimilar fabrics (Lev. 19:19) as well as laws concerning cutting hair and tattoos (Lev. 19:27–28).
The second sphere in which the Lord called Israel to be holy was in relation to the other nations. “You shall be holy to me; for I the Lord am holy, and I have separated you from the other peoples to be mine” (Lev. 20:26). Moses said that if Israel would follow God’s laws then the nations would take notice of the Lord’s nearness to his people because of their great wisdom and understanding (Deuteronomy 4:6–8). This is a powerful reason for the people of God to express God’s holiness in their daily behavior. Wright affirms this missional motive by stating, “Religious distinctiveness was to be embodied in ethical distinctiveness, both of which are included in the rich concept of holiness. And it would be this ethical distinctiveness of Israel that would be a pointer to the presence of the ethical God, YHWH, in their midst.”
So holiness in Leviticus is not separation for separation’s sake, but for the sake of a thriving community of the people of God and the reconciliation of each person to God. Holiness is not only about individuals’ behavior following regulations, but about how what each person does affects the whole people of God in their life together and their work as agents of God’s kingdom. In this light, Jesus’ call for his people to be “salt” and “light” to outsiders (Matthew 5:13–16) makes complete sense. To be holy is to go beyond the law to love your neighbor, to love even your enemy, and to “be perfect, therefore, as your heavenly Father is perfect” (Matthew 5:48, echoing Leviticus 19:2 and 18).
In short, ancient Israel did not obey Leviticus as a peculiar set of regulations, but as an expression of God’s presence in their midst. This is as relevant to God’s people today as it was then.