Our Gemara on Amud Beis delves into the sources and specific laws concerning the automatic release of a Canaanite slave whose master causes him to lose a limb. While the scripture mentions a tooth or eye, the halakhic interpretation extends it to any limb (See Shemos 21:27).

Sefer Daf Al Daf presents an insightful derush and analysis of Aggadah by Rav Tzvi Pesach Frank (Vaera 6:5). When Moshe expresses concern over the continued suffering of the Jewish people and their yet-to-be-realized redemption, God responds by saying, "I have now heard the moaning of the Israelites because the Egyptians are holding them in bondage, and I have remembered My covenant."

There are two elements to this statement: God's acknowledgement and notice of the suffering and His remembrance of the covenant.

The Gemara (Berachos 5a) discusses how suffering acts as a means of cleansing a person from sin. It draws an a fortiori inference from the law concerning the tooth and eye of a slave: If the loss of a single limb results in the slave's freedom, then suffering, which affects the entire body, would surely bring about freedom and atonement from sins.

Rabbi Shimon ben Lakish further explores the metaphor of suffering being akin to salt. Just as salt enhances the taste of meat, suffering purifies a person's transgressions, preparing them for a more elevated existence.

Rav Frank's interpretation emphasizes the distinction between the metaphors of being set free via "tooth or eye" and suffering as salt. The tooth and eye metaphor relates specifically to suffering orchestrated by divine providence. In contrast, the metaphor of salt encompasses suffering experienced through the normal vicissitudes of life, including those inflicted by the Egyptians without God's explicit direction.

Rav Frank suggests that even suffering not directly caused by divine intervention can still merit forgiveness and freedom from servitude. Perhaps, one might think that, since the Egyptians were the ones inflicting the suffering on the Jewish people, it is not coming via divine providence, and therefore it would not expunge their sins, nor merit their redemption. This is why the first ends with, “and I also remember my covenant.“ This is alluding to the covenant of salt (see Vayikra 2:13). Specifically the salt described by Reish Lakish, the sufferings of everyday life that also provide expiation and can merit redemption. Even if pharaoh was inflicting suffering on the Jewish people coming from his own free will, and not God‘s direction, this suffering still would merit forgiveness, and therefore freedom from servitude.

This understanding highlights the significance of perceiving day-to-day suffering with the right attitude, as it can serve as expiation for sin.