During the time of the Babylonian siege, the king and princes of Jerusalem decided to free all the slaves in a sweeping manner in order to alleviate the situation of the city under siege. During a time of siege, slave ownership can be a great burden on their masters, who must support both their own families and their slaves. During a siege, many slaves became useless, as they generally engaged in field work outside the city. On the other hand, liberating the slaves and turning them into free men can contribute to the resilience of a city under siege as freed slaves are likely to fight alongside the people of the city and help fortify it in order to maintain their freedom. However, as soon as the Babylonian army left Jerusalem and the siege was lifted, the motive for liberating the slaves was cancelled, and the people therefore restored the slaves to their previous status.
As opposed to the breach of the covenant in chapter 11 in which Yirmiyahu describes the violation of many many mitzvot, here only one mitzva is violated. Why were the people punished so severely for the violation of a single commandment?
The Covenant at Sinai is based on the principle that the liberty granted to Israel upon their leaving Egypt is the foundation for the freedom which they must grant to their slaves. In contrast, in our passage, we learn of a breach of this covenant. In this breach, the people take a step towards repentance and transform that step into a sin thereby making it even more severe.
Abridged and adapted by HaTanakh.com Staff. For further reading, see the full article.