A whole generation (or more) of people has grown up hearing the adage, “cleanliness is next to godliness.” And I — like many others — heard many encouragements in my early years to make things “spic and span.”
Importing those notions into the text of Leviticus is not helpful to understanding what God is saying through Moses about those who are clean and unclean. Moses is not speaking of something that is physically clean or even hygienically clean. So of what is he speaking? It obviously is a significant idea to him, since he uses the word “clean” 46 times in Leviticus (and 35 times in chs. 11-15) and “unclean” 116 times (94 times in chs. 11-15). It is apparent from the extent of the usage of these words alone that he’s communicating something! But what?
The temptation is to say that he’s speaking of that which is morally pure or morally impure, but closer examination eliminates those possibilities. While certain foods and activities are declared “unclean,” to eat or touch something unclean or engage in an unclean activity left that individual unclean for the remainder of the day (typically, though sometimes longer), but there was no punishment attached to that violation. In other words, though “unclean,” it was always temporary. Also, that inherent morality is not in view with these terms is clear from Acts 10, when both unclean animals and men were declared to be clean. If sin is inherently meant by “unclean” in Leviticus, it would not be declared clean in Acts.
So what do these terms mean? The use of “clean” and “unclean” is to demonstrate to the Israelites their distinctiveness from the nations. In every area of their lives — both moral and ceremonial — the actions of their lives are set apart to God in ways that clearly distinguish them from the Gentile (unbelieving) nations.
In all of this, God is teaching His people to live antithetically. That is, He is using those clean and unclean distinctions to separate Israel from other idolatrous nations who have no such restrictions, and He is illustrating by these prescriptions that His people must learn to live His way. Through dietary laws and rituals, God is teaching them the reality of living His way in everything. They are being taught to obey God in every seemingly mundane area of life, so as to learn how crucial obedience is. Sacrifices, diet, and even clothing and cooking are all carefully ordered by God to teach them that they are to live differently from everyone else. This is to be an external illustration for the separation from sin in their hearts. Because the Lord is their God they are to be utterly distinct. In v. 44, for the first time the statement “I am the Lord your God” is made, as a reason for the required separation and holiness. After this verse, that phrase is mentioned about 50 more times in this book, along with the equally instructive claim, “I am holy.” Because God is holy and is their God, the people are to be holy in outward ceremonial behavior as an external expression of the greater necessity of heart holiness. The connection between ceremonial holiness carries over into personal holiness. The only motivation given for all these laws is to learn to be holy because God is holy. The holiness there is central to Leviticus (see 10:3; 19:2; 20:7, 26; 21:6-8).