The Torah principles of judgment are scrupulously fair. They may favor neither the low nor the high: “don’t favor the poor man, nor glorify the great” (Vayikra 19:15). Fundamentally this applies also to balancing the claims of worker and employer, but in this case the halakha tips the balance slightly in favor of the worker – perhaps because he is considered to be at an inherent disadvantage.
Many of the principles favoring workers are learned from parshat Behar. There is a general principle in halakha that “Whoever backs out of an agreement has the lower hand” – he must indemnify the other side for the costs of his renegeing (Bava Metzia 76a). Yet there is an exception to this rule: a worker who quits in the middle of the agreed upon work period is not subject to any penalty. Even this slight amount of duress discouraging the worker from quitting would violate the high degree of worker’s autonomy dictated by our parsha (Vayikra 25:55): “For the children of Israel are slaves to Me” – slaves to HaShem, and not slaves to their fellow man (Bava Metzia 10a).  There is another rule that “Any stipulation in monetary affairs is binding” (Ketubot 56a). Therefore, the employer should be able to occupy the worker in any work which is permitted by the work agreement. However, our parsha forbids giving busy-work to a Hebrew servant (Vayikra 25:43) – “Do not tyrannize him”; and some commentators infer that it is improper to give busy-work to an ordinary employee as well (Chinukh 346; see Responsa Maharam Rothenburg 4:85).
There are also other halakhot establishing lenient exceptions for workers, which are not learned from our parsha. Here are a few: In general, an oath is valid only to avoid paying a judgment, not to exact payment from someone else. Yet the Beit Din will obligate the employer to pay based on the oath of a worker who claims he has not been paid (Shavuot 44b). Our Sages perceived a fundamental lack of symmetry in this situation: The employer has many employees and can’t pay attention to each one, but the worker has his heart and soul set on getting his pay.  An agent is supposed to faithfully serve the interests of his sender. Yet if an employer offers to hire workers for a specified amount and his agent succeeds in hiring them for less, the workers are justified in resentment of the agent who prevented them from enjoying the extra payment – even though this payment was at the employer’s expense (Bava Metzia 76a; see Melo Haroim).  Normally, failing to pay a debt is a “sin of omission”. However, failing to pay a worker during the same night or day that his payment is due transgresses a Torah prohibition. Even afterwards, neglecting to pay the worker’s salary is considered a “sin of commission” like actual stealing (SA CM 339:1-2, Rambam Sekhirut 11:2. According to Lechem Mishna Gezeila 1:3 this applies to no other kind of debt). The reason again is that the worker has his heart set on his pay (Devarim 24:15).
In the Western tradition, justice is portrayed as blind. The Torah, however, allows us to open our eyes a bit to balance institutionalized inequality.