Halakhah su Levitico 25:43

That He prohibited us from working a Hebrew (Jewish) slave with something that we do not need. And that is called oppressive work (avodat perech). And that is His, may He be blessed, saying, "You shall not rule over him oppressively" (Leviticus 25:43). And the language of the Sifra (Sifra, Behar, Section 6:2) is, "'You shall not rule over him oppressively' - that [he] should not tell him, 'Heat up this cup [of water] for me,' but he does not need it," and all that is similar to this. However they brought an example from the easiest of jobs and the simplest of them - that in spite of that, it is not permissible except when it is needed. (See Parashat Behar; Mishneh Torah, Slaves 1.)

To not make a Hebrew slave perform oppressive work: To not make a Hebrew slave do oppressive work, as it is stated (Leviticus 25:43), "do not subjugate him with oppressive work." And what is oppressive work? They, may their memory be blessed, explained (Sifra, Behar, Section 6:2) that it is work that does not have a limit, and so [too,] work that a person does not need but he does it so that the slave not be idle - and like they, may their memory be blessed said, "A man should not say to him, 'Hoe underneath the vines until I come,' as behold he has not given him a limit; but rather he should say to him, 'Hoe until x hour,' or 'until place y.' And they also said in Sifra that he should not say to him, "Heat this cup for me," when he does not need it; and all that is similar to it. But they, may their memory be blessed, brought an example of the lightest type of work and the quickest to do - and all the more so [is it the case with] other ones. And the principle is that we only make him do work that we have a need for that work that we commanded him. The details of the commandment are short, and behold I have written a few of them.