Comentario citado sobre Números 23:26

ואל כליך לא תתן, “but you must not put any of it into your vessel.” This would be considered robbery. The Torah made a concession only concerning the desire of a person to eat on the job when he is tempted greatly to immediately gratify his appetite. Had the Torah not given its blessing to the laborer to eat ad hoc, he would have done so as a thief, something far worse. This is why the Torah adds the significant restriction כנפשך שבעך, “until you have satisfied your immediate craving.” The expression שבעך is reminiscent of Proverbs 13,25: “the righteous eats to his heart’s content;” Solomon means that he does not eat as a glutton, only to still his hunger. The same considerations apply to the laborer working in a grain field as outlined in verse 26. He must use his hands and not a tool (sickle) in order to cut down grain for personal consumption.