If a Jewish slave who has an obligation to work for his master for six years fell ill for three of those years, he has no obligation to make them up by working another three years when his six-year servitude is completed.

Does this rule apply as well to a teacher or worker who has been hired for a long period and is unable to work for a substantial amount of time because of illness?

This is the subject of a major debate between the early commentaries. Tosefot cites the opinion of some authorities who compared the teacher to the slave and considered him entitled to full compensation without a need to make up for the time lost because of illness. This opinion appears in the commentary of Rabbi Mordechai bar Hillel Ashkenazi (Mesechta Bava Metzia, par. 347). It is based on the fact that if the slave who did something wrong (either by stealing or by selling himself into slavery against the wish of Hashem, Who wants Jews to be slaves only to Him and not to His slaves) is given such consideration, then this leniency should certainly apply to the teacher who did nothing wrong.

Tosefot, however, rejects this comparison between slave and teacher. One of the distinctions he makes is that the slave is considered the property of the owner during the six years of his servitude and the payment he received was for giving his master this ownership. His obligation to his owner is only to work as much as he is able; if he is unable to work because of illness, he has no obligation to make up for lost time. The teacher, on the other hand, is not the property of his employer and merely contracts to perform a service for pay. His failure to provide this service because of illness does therefore not entitle him to compensation.

Other distinctions are made by Tosefot here and by Rosh in mesechta Bava Metzia (sixth perek par. 6). The latter cites the opinion of Rabbi Meir that if the owner paid the teacher in advance then he has no obligation to make up the time lost because of illness. But if he has not yet paid him he must make up the lost time if he wishes to be paid in full. Both the opinion of Tosefot and the qualification of Rabbi Meir are cited by Rema (Shulchan Aruch Choshen Mishpat 333:5) as halachic conclusions.

The condition of the Jewish slave, who is the subject of so much of the first perek of our mesechta, was radically different from the image that the word slavery conjures up in our minds.

In Biblical and Talmudic times a Jew could become a slave in one of two ways. If he was convicted of theft and lacked the funds to compensate his victim, the court sold him into slavery for six years so that the money paid by his purchaser could be used for such compensation. There was also the possibility of a Jew who reached such a desperate level of destitution that the only way he could provide for himself and his family was to sell himself as a slave.

In either case, the Torah laid down severe restrictions on the manner in which such a slave is sold and the nature of the work which can be assigned to him. These restrictions were to insure that his dignity as a Jew was maintained. As if these restrictions were not enough to achieve this goal, the Torah explains the reasons for a slave wishing to stay on with his master when his six-year period is over as "for it is good for him to be with you" (Devarim 15:16). This is interpreted by our sages as a directive to the owner of a Jewish slave to assure that he enjoys the same quality of food, drink and sleeping accommodations as his master, a requirement which led the sages to conclude that "one who purchases a Jewish slave is buying himself a master instead."

Tosefot raises the question as to why the Jewish slave is considered like a master to his master when all that is demanded of his master is to show him equality? As an answer Tosefot cites the Jerusalem Talmud which discusses the case of a master who has only one good mattress in his possession. If he keeps it for himself and relegates the slave to a bed of straw, he has not fulfilled the requirement of equality. To withhold the use of the mattress from both would be behaving with Sodomite insensitivity. The only course available then is to give the mattress to the slave, which in a sense makes him enjoy the status of master of his master rather than being his slave.

Kiddushin 20a