19 Ye shall keep my statutes. Thou shalt not let thy cattle gender with a diverse kind: thou shalt not sow thy field with mingled seed: neither shall a garment mingled of linen and woollen come upon thee.
Verse 19 is about keeping things separate and pure, not mixing parts together. It can be seen as a continuation of the laws against eating unclean meat and not using leaven during the Passover. All of this, of course, is a symbol of being a separate and chosen people. Though Israel would necessarily live alongside pagan cultures, they were not to mix faiths, not to corrupt their worship of God. Unfortunately, Israel would on many occasions fall into this very error and would lose their kingdom because of it.
Of course, we cannot judge them too harshly. Corruption of the faith is a very real problem in our day, too. There are many “Christians” who are more converted to the trends of our current society than their actual doctrine, seeking to blend fabrics of love and tolerance with sins like homosexuality, to give just one example. Mankind has ever been too concerned with looking right according to the current social standard, and not in being right in God’s eyes.
It is interesting that it is this particular verse has become a favorite go-to for those wanting to discount the Bible’s commandments against homosexuality. “Why do you hold to the Bible’s condemnation of gay people, but you still wear clothes with mixed fabrics?” The answer is that, as previously mentioned, the mixed fabric law was part of the unclean meats and leaven laws, which was explicitly withdrawn in Acts 10, whereas the sins of sexual immorality have never been rescinded. Still, it is ironic and poetic that people attempt to justify homosexuality by referencing the very category of commandments that symbolically opposed the mingling of faith with the immoral trends of the day.