And the LORD spake unto Moses and to Aaron, saying unto them, Speak unto the children of Israel, saying, These are the beasts which ye shall eat among all the beasts that are on the earth. Whatsoever parteth the hoof, and is clovenfooted, and cheweth the cud, among the beasts, that shall ye eat. Nevertheless these shall ye not eat of them that chew the cud, or of them that divide the hoof: as the camel, because he cheweth the cud, but divideth not the hoof; he is unclean unto you. And the coney, because he cheweth the cud, but divideth not the hoof; he is unclean unto you. And the hare, because he cheweth the cud, but divideth not the hoof; he is unclean unto you. And the swine, though he divide the hoof, and be clovenfooted, yet he cheweth not the cud; he is unclean to you....The carcases of every beast which divideth the hoof, and is not clovenfooted, nor cheweth the cud, are unclean unto you: every one that toucheth them shall be unclean. (Lev. 1-7, 26)
And every beast that parteth the hoof, and cleaveth the cleft into two claws, and cheweth the cud among the beasts, that ye shall eat. Nevertheless these ye shall not eat of them that chew the cud, or of them that divide the cloven hoof; as the camel, and the hare, and the coney: for they chew the cud, but divide not the hoof; therefore they are unclean unto you. And the swine, because it divideth the hoof, yet cheweth not the cud, it is unclean unto you: ye shall not eat of their flesh, nor touch their dead carcase. (Deut. 14.6-8)
The Letter of Aristeas (c. 2nd century BC), 153-155:
For all cloven-footed creatures and ruminants quite clearly express, to those who perceive it, the phenomenon of memory. Rumination is nothing but the recalling of (the creature's) life and constitution, life being usually constituted by nourishment, wherefore he exhorts us in the Scripture also in these words: 'Thou shalt surely remember the Lord that wrought in thee those great and wonderful things' (Deut. 7.18; 10.21).
Philo of Alexandria, De Specialibus Legibus 4.107:
For just as a cud-chewing animal after biting through the food keeps it at rest in the gullet, again after a bit draws it up and masticates it and then passes it on to the belly, so the pupil after receiving from the teacher through his ears the principles and lore of wisdom prolongs the process of learning, as he cannot at once apprehend and grasp them securely, till by using his memory to call up each thing that he has learned by constant exercises which act as the cement of conceptions, he stamps a firm impression of them on his soul.
But his delight is in the law of the LORD; and in his law doth he meditate day and night. (Ps. 1.2)
Samuel Smith, David's Blessed Man (re Ps. 1.2):
For without this meditation this law, which is the word of God, will either in time be forgotten, whereby we shall become unmindful of it, or else it will prove as a talent hid in the ground, utterly unfruitful unto us, for this meditation indeed is the third step of a true convert. The first is to hear the word of God readily; the second to remember it diligently; and the third to meditate on it seriously; and this is compared to the 'chewing of the cud,' Deut. xiv. 6, 7, which is never found in the unclean but in the clean beasts....Use 2. This may admonish all men, as they love their own souls, to make more care and conscience of the performance of this duty, to call to mind that we do hear or read, to think and muse upon it, to chew the cud, to lay it to heart, yea, and to apply it to our own souls and consciences in particular. This is like the rumination or chewing of the cud to be found only in the clean beasts, whereas they which chewed not the cud were unclean, Deut. xiv. 6, 7.
Bartholomew Ashwood, Heavenly Trade (re Ps. 1.2):
Meditation chews the cud, and gets the sweetness and nutritive virtue of the Word into the heart and life: this is the way the godly brings forth much fruit.
Thomas Watson, A Christian on the Mount, p. 2 (re Ps. 1.2):
Doctrine. The proposition that results out of the text is this, that a good christian is a meditating christian. "I will meditate in thy precepts," Ps. cxix.15. "Meditate upon these things," 1 Tim. iv.15. Meditation is the chewing upon the truths we have heard: the beasts in the old law that did not chew the cud, were unclean; the christian that doth not by meditation chew the cud, is the be accounted unclean.
I will meditate in thy precepts, and have respect unto thy ways. (Ps. 119.15)
George Horne, A Commentary on the Book of Psalms, p. 523 (re Ps. 119.15):
Meditation is that exercise of the mind, whereby it recalls a known truth, as some kinds of creatures do their food, to be ruminated upon, until all the nutritious parts are extracted, and fitted for the purposes of life. By study we lay in knowledge, by meditation we reduce that knowledge to practice.