John Calvin Commentary Deuteronomy 22:9

"Thou shalt not sow thy vineyard with two kinds of seed, lest the whole fruit be forfeited, the seed which thou hast sown, and the increase of the vineyard." — Deuteronomy 22:9 (ASV)

You shall not sow your vineyard. These four precepts, which all condemn strange mixtures, I do not doubt are supplements to the First Commandment. The reason, which is added in Deuteronomy, supports this understanding, as God declares there that the produce of the seed and of the vineyard is polluted if there are diverse mixtures. From this it appears that nothing else is demanded of them but that they cultivate purity.

Indeed, the word Moses uses means “sanctify” (the Hebrew term is קדש kadesh); but by antiphrasis, it is taken to mean “contaminate.” What follows is to the same effect: they should not plow with an ox and an ass together. This diversity is forbidden for no other reason than that people contract some defilement as soon as they depart from simplicity.

Yet, if anyone thinks otherwise, I will not strongly argue with them. It might indeed be objected that when God forbids animals of different kinds to be used indiscriminately or mixed together, He is concerned with chastity,³⁰ and that by forbidding fields to be sown with different seeds and garments to be woven with different materials, He intended to prevent fraud.

But the simpler explanation is that the people were thus kept in purity, to prevent them from accustoming themselves to corrupt habits, bringing in strange rites from various sources, or seeking, with depraved curiosity, mixtures that might eventually invade the worship of God.

For if animals of different species are joined together, the integrity of nature is corrupted, and a corrupted offspring is produced, which degenerates from God’s established order. However, if various kinds of seed were mixed, or if a garment were woven of linen and wool, there would be no danger of deception or fraud in such an obvious matter.

It is probable, therefore, that the purpose God intended, as I have said, was that by cultivating natural and simple habits throughout their lives, they should keep themselves pure and uncorrupted from every foreign vice.

For this reason, Scripture compares strange doctrines to leaven, since by their additions or omissions they corrupt the pure word of God (Matthew 16:11). This was by no means a useless discipline; for in trivial matters, and things of almost no consequence, they were restrained so that they would not deviate from purity in the slightest degree.

It was a small matter to interweave a thin thread with a thicker one, and perhaps such a process would have been beneficial for their general advantage. In some fields, too, a better crop is grown if the seed is a compound of pure wheat and some other sort of grain (siligine). Similarly, the union of the horse and ass has been approved of, since mules are produced this way.

But God would not allow these things among His ancient people, to prevent them from gradually sinking into greater license, where they might eventually adopt the practices and customs of the pagans.

He therefore uses this preface: “You shall keep my statutes” (Leviticus 19:19), from which we gather that the people were surrounded with fixed barriers. This was so they would not defile themselves with foreign vices and imitate the nations from which they had been separated. Therefore, the essence of the matter is that they should abide in God’s statutes.

³⁰ “Au septieme commandement de la Loy, qui est d’observer chastet;” to the Seventh Commandment of the Law, which is to observe chastity. — ;” to the Seventh Commandment of the Law, which is to observe chastity. — Fr..