“And thou shalt remember that thou wast a bondman in the land of Egypt, and the L-RD thy G-d redeemed thee.”
– Deuteronomy 15:15-18, JPS 1917 Tanach
Because the Israelites were taken out of Egypt, having been freed from slavery, we are no longer meant to be slaves in perpetuity. Yet, certain circumstances would lead to a Jewish person having to sell himself as a servant to another person. This included when a thief was unable to make good on a return of the items, monetarily that he had stolen.
And, so, the midrash addresses this circumstance: “the ear which had heard G-d say at Mount Sinai: ‘do not steal,’ and which had heard G-d say: ‘the Children of Israel are My slaves,’ needs to be reminded of this by being pierced after having opted to ignore both of these statements by G-d” (Chizkuni on Deut. 15:17, citing Rashi; sefaria.org).
In other words, it is an insult to G-d as well as oneself, to disregard the status given to us at Sinai, via the covenant. G-d’s people are meant to serve Him; we should not forsake that priority, by serving another. Even so, we should not enslave ourselves to anything, that would deprive of us serving G-d, by way of the commandments.
To voluntarily choose a life that is devoid of acknowledging the One Who brought us out of bondage, is to forsake the purpose of our freedom. Unless careful consideration is given to the reason that G-d brought us out of Egypt, we will not have the full picture.
According to chazal (the sages), after being freed from physical bondage, G-d gave us the Torah, so that we would have a moral compass, in our lives, in order to prevent us from enslavement to sin. Therefore, by serving G-d, we are able to transcend our lower inclinations, that would otherwise compel us to stray from our pursuit of righteousness.