Prov 23:2

“and you shall put a knife into your jaw Heb. בלועך, into your jaw. If you see that he is stingy, do not eat of his [food]. if you are a man with a hearty appetite If you are a glutton and long to eat, it is better that you thrust a knife between your teeth. Our Sages expounded this as referring to a disciple sitting before his teacher. If he knows that his teacher will give him an answer for everything he asks, let him investigate the subtle points and ask concerning his tradition, but if not, let him keep his peace.”

“And put a knife to thy throat,.... Refrain from too much talk at the table; give not too loose to thy tongue, but bridle it, considering in whose presence thou art; do not use too much freedom, either with the ruler or fellow guests; which, when persons have ate and drank well, they are too apt to do, and sometimes say things offensive to one or the other; it is good for a man to be upon his guard; see Ecc 5:2. Or restrain thine appetite; deny thyself of some things agreeable, that would lead thee to what might be hurtful, at least if indulged to excess: put as it were a knife unto thine appetite, and mortify it; which is the same as cutting off a right hand, or plucking out a right eye Mat 5:29. Or while thou art at such a table, at such a sumptuous entertainment, consider thyself as in danger, as if thou hadst a knife at thy throat; and shouldest thou be too free with the food or liquor, it would be as it were cutting thine own throat; if thou be a man given to appetite; there is then the more danger; and therefore such a person should be doubly on his guard, since he is in the way of temptation to that he is naturally inclined to. Or, "if thou art master of appetite" (r): so the Targum, "if thou art master of thy soul;'' if thou hast power over it, and the command of it, and canst restrain it with ease; to which agrees the Vulgate Latin version: but the former sense is more agreeable to the Hebrew idiom. (r) "dominus animae", Vatablus, Mercerus, Michaelis.”

“Throat. Restrain intemperance and talkativeness, Ecclesiasticus xxxi. 12. Septuagint, “stretch forth thy hand, knowing that thou must prepare the like; but if thou be more insatiable, ( 3. ) desire not his meats, for he has them of a deceitful life.” They cannot afford real happiness, (Haydock) and to vie with the rich would only reduce them to poverty, Ecclesiasticus xiii. 2. St. Augustine (tr. xlvii. in Joan.) explains this text of the blessed Eucharist, observing, that we must give our life for our brethren, as Christ did for us. Before communion, we must slay the old man, and subdue our passions. (Calmet) — Power. Protestants, “if thou be a man given to appetite.” The situation of a courtier is very critical. (Haydock) — Those who eat with the kings of Persia, were nicely observed by an eunuch, lest they should cast their eyes on any of his concubines. (Lucian. de Merced.)”