Maasrot, Chapter Two, Mishnah Seven
According to the rabbinic interpretation of Deuteronomy 23:25-26, the Torah allows a worker in a field to eat from the owners produce while he is working in the field (see also Bava Metzia 7:2). The produce that he eats is not considered a wage and hence it can be eaten without having been tithed. Our mishnah deals with several ramifications of this law.
1) One who has hired a worker to help him harvest figs, and he [the worker] said to him On condition that I may eat the figs, he may eat them and he is exempt [from tithing].
2) [If he said,] On condition that I and my son may eat, or that my son may eat of them in lieu of my receiving a wage, he may eat and he is exempt [from tithing], but his son may eat but he is liable [for tithes].
3) [If he said,] On condition that I may eat of them during the time of the fig harvest, and after the fig harvest, during the time of the fig harvest he may eat and he is exempt [from tithing], but if he eats after the fig harvest he is liable, since he does not eat of them in the manner mandated by the Torah.
4) This is the general rule: one who eats in a manner mandated by the Torah is exempt [from tithes], and one who does not eat in the manner mandated by the Torah is liable.
Section one: As I explained in the introduction, the worker is allowed to eat while harvesting the grapes, even if he doesnt stipulate that he may do so. Therefore, the fact that he says, On condition that I may eat the figs does not make the figs part of the contract and thereby like wages; rather he is allowed to eat the figs because of the Torahs laws. Since the figs are not considered part of his wages, he may eat them without tithing.
Section two: The Torah does not mandate that a workers son can eat of the produce while his father is working in the field. Therefore, if the worker makes this stipulation the figs that his son eats are considered wages and must be tithed before the son eats them.
Section three: The Torah mandates that he is allowed to eat while he is harvesting but not after the harvest has been completed. Thus, while still harvesting he can eat the figs without tithing them. However, if he eats figs after the harvest has been completed, these are considered to be wages and he must tithe them before he eats.
Section four: The general rule here is the basis of all the previous section. It is interesting to note that what the Torah mandates that the employer give his employee is not considered a wage, but a right.