Why does God say not to mix fabrics?

The instruction not to mix fabrics comes from the Hebrew Bible, specifically Leviticus 19:19 and Deuteronomy 22:11, which states you shall not wear a garment made of wool and linen woven together, known in Hebrew as shatnez. This is part of a group of laws in Judaism called chukim, which are decrees that do not have an obvious rational explanation and are observed as an act of obedience to God. Over centuries, scholars have offered several interpretations. One traditional Jewish explanation is that mixing species or materials blurs the distinct categories God created in the world and is meant to preserve the integrity of creation. Some rabbis teach it is about maintaining boundaries and holiness through separation. Another historical explanation is that ancient pagan priests wore mixed wool and linen garments during idolatrous rituals, so Israelites were commanded to avoid that practice. Some suggest it was a way to preserve quality, since wool and linen shrink differently and mixing would ruin clothing. In Orthodox Judaism, the law is still observed today and garments are checked for shatnez. Most Christian denominations consider this part of ceremonial Old Testament law that is no longer binding.