In the laws of workers, the gemara has little discussion of the employer’s social obligations toward the worker or vice versa. One could almost suffice with the general rule that the mishna (Bava Metzia 83a) sets down: "One who hires workers and then told them to come early and leave late: if it is a place where the practice was not to wake up early and leave late, he is not allowed to force them. If it is a place where the practice is to feed [the workers], he should feed… Everything follows the practice of the place."
The main discussion in the gemara is about the power of the connection between employee and employer. How is it created? Under what conditions can one abrogate the agreement? What compensation is provided to one side when the other does not fulfill his obligation?
The baraita (Bava Metzia 76b) states: "One who hires craftsmen and they deceived the employer or the employer deceived them, neither has rights to the other beyond taromet (moral grounds for grievance). When are these words said? When they did not go, but if donkey drivers went and did not find grain, or workers went and found a moist field, they have to pay their salary in full. However, one who comes [back] with a load cannot be compared to one who comes empty-handed, [nor can] one who does work [be compared to] one who sat idly by." The rule then is that if the workers just went to begin their work, the employer already became obligated to employ them and cannot back out. However, until that point, neither side is obligated to the other, beyond the matter of taromet considerations. Many Rishonim (including the Nimukei Yosef 46b in the pages of the Rif) say that the beginning of the job is like a kinyan (an act of finalization).
Tosafot points out that, at times, an employer cannot back out even before the worker sets out to begin his task. In a case where, due to prior agreement between the parties, the worker turned down other employment opportunities and if the employer backs out they will be unable to replace the work with another job, the employer must compensate the worker for the lost income even if the work was not begun. Tosafot explains that the reason for this compensation is the laws of garmi (semi-direct damages). The K’tzot Hachoshen (333:1) asks that we find obligations of garmi only for losses. In this case, though, the worker does not lose something existing but just does not have the opportunity to gain as he might have. Indeed he cites Rishonim who do not make such an employer pay. The Ramban says that the payment is not one of damages but stems from an obligation that an employer tacitly accepts upon himself to pay should the situation arise. The Netivot Hamishpat (333:3) says that the obligation is only of rabbinic origin, designed to deal with a social problem.