John Wesley on Deuteronomy 22:9

Divers seeds - Either With divers kinds of seed mixed and sowed together between the rows of vines in thy vineyard: which was forbidden to be done in the field, Lev 19:19, and here, in the vineyard. Or, With any kind of seed differing from that of the vine, which would produce either herbs, or corn, or fruit - bearing trees, whose fruit might be mingled with the fruit of the vines. Now this and the following precepts, tho' in themselves small and trivial, are given, according to that time and state of the church, for instructions in greater matters, and particularly to commend to them simplicity in all their carriage towards God and man, and to forbid all mixture of their inventions with God's institutions in doctrine or worship. Defiled - Legally and morally, as being prohibited by God's law, and therefore made unclean; as on the contrary, things are sanctified by God's word, allowing and approving them, 1Tim 4:5.