Leviticus 11:22
Even these of them ye may eat; the locust after his kind, and the bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind. Even these of them ye may eat; the locust after his kind, and the bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind.
The verse belongs to the food law in Leviticus 11 given through Moses that distinguishes creatures permitted for food from those declared unclean and forbidden to eat. Within that law it specifically permits four kinds for food, the locust after his kind, and the bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind, while even the smallest insect outside this permission could be classed among the unclean. This law was given to Israel as health teaching enforced as sanitary rules during wilderness training before entering Canaan.
The restrictions were not arbitrary but were given to preserve life and health by keeping the blood pure through simple, healthful food and by limiting the harmful effects of eating animal food. Swine's flesh and the flesh of certain other animals were forbidden because they fill and pollute the blood with impurities and shorten life, and other animals were forbidden because they were not the best articles of food. Swine were particularly hurtful, filling the system with humors and in that warm climate often producing leprosy, with an influence upon the system far more injurious there than in a colder climate. They were never designed to be eaten under any circumstances but were useful as scavengers where much decayed upon the ground that would otherwise poison the atmosphere, devouring the decaying substances as a means of preserving health.
If Israel had submitted to these prohibitions, everything injurious to health would have been removed from them and no sickness suffered to be among them, but because they would not submit they were given what they lusted for. Daniel and his companions refused the king's fare because it included meats this law pronounced unclean, in order to preserve clear minds and physical health for service to God. Later religious leaders did not leave these restrictions as given but burdened them with added traditions and unwarranted extremes, requiring all water used to be strained lest it contain the smallest insect and turning food distinctions into a continual source of anxiety and ceremonial observance. That straining of tiny insects was condemned as trivial attention to outward cleanliness while serious sins went unchecked.