These three commands have the same general thought behind them. They move from concrete to intention, that is, from letter to spirit. The one regarding cloth is easiest to illustrate this principle. The specific application involves linen and wool, and Israel was not to mix the fibers from a vegetable product and an animal product into the same piece of material. It expands in its practical application when we understand that mixing animal and vegetable fibers makes poor quality material. Therefore, the intent—its spirit—is to teach us to purchase the best quality that we can afford.
The same holds true with the other laws that appear in this context. God is instructing us that the best thing to do is to keep the breeds pure and not let hybrids develop. The pure breeds of a species are always considered to be of higher quality.
Why was it done this way? It has to do with the Old Covenant and God's intention in His use of the children of Israel. It was not God's intention at the time to save them. He was producing a historical record so that the church of God, whom He did intend to save, could understand things much more clearly—His purpose—and make proper applications of those laws, examples, and principles to their lives.
John W. Ritenbaugh
The Covenants, Grace, and Law (Part 18)
Leviticus 19 deals with social relationships within the community, and these commandments are seen as major regulators of community relationships. God gives all of these laws with a common thought in mind: "You shall be holy, for I the LORD your God am holy." These laws are given because the Lawgiver is God (see verses 4, 10, 12, etc.).
They are not primarily statements of authority ("Do this because I tell you"), though some of this is included, but statements of the relationship between the Lawgiver and His law. The laws reflect His nature. The law is what it is because God is what He is. Therefore, if we want to be like God, we will imitate Him by obeying His laws in their physical and spiritual applications.
John W. Ritenbaugh
The Fifth Commandment (1997)
Should a Christian Wear Clothing of Mixed Fibers (Leviticus 19:19)?
This question often arises when people read Leviticus 19:19 and Deuteronomy 22:11. Today we would call this a "consumer protection law." Notice that these verses contain the basic principle that materials of widely differing character and texture are not to be combined. On the other hand, these verses allow a number of combinations that are within God's laws.
Today's garments are made of two basic kinds of natural fibers. The first is plant cellulose fiber, from which fabrics such as linen and cotton are produced. The second is animal protein fiber such as wool and silk. Because these kinds of fibers differ markedly in strength, washability, absorption, and so forth, they should not be mixed.
However, a garment made of a combination of cellulose materials—a mixture of cotton and linen, for example—is acceptable because the fibers are basically similar. For the same reason, mixtures of protein fibers (wool, mohair, silk, and so on) are acceptable.
What about the mixture of synthetic, man-made fabrics, such as Dacron, nylon, polyester, and rayon, with either cellulose or protein fibers? Many have not realized that a combination of synthetic and either plant or animal material does not necessarily break the biblical principle. Synthetic materials are usually made to have essentially the same characteristics as the natural fibers. Otherwise, they would not mix well. The stronger fibers would cut and tear away from the weaker ones or would not combine well in other ways. In other words, it is perfectly acceptable to manufacture fabrics from a combination of fibers which are naturally or artificially compatible with one another. It is the mixture of fibers with markedly differing qualities which this biblical principle concerns.
It should be noted that such combinations produce a cheaper garment, with respect to quality, than one made with the best grades of pure fibers. On the other hand, a fabric made from low-grade, natural fibers is usually improved by the addition of compatible man-made fibers. Any good tailor or seamstress knows that the best quality clothing is made from 100 percent wool, cotton, and so forth. Nevertheless, one need not throw away or destroy clothing which may be of lower quality or a wrong mixture. Wearing such materials is not a sin in itself. Rather, God does not want manufacturers producing shoddy materials in order to take advantage of their customers.
A wise principle to follow in selecting either a pure or mixed garment is to purchase the best quality one can afford—it will last longer and fit better than inferior, less expensive clothes. The primary reason to do this is to honor and glorify God in what we wear, especially if the clothing is to be worn primarily for church services. However, it is not wise to go into debt buying better quality than one can afford.
Wool and Linen
Other Forerunner Commentary entries containing Leviticus 19:19: