What does Leviticus 25:10 mean in context?

The Liberty Bell has an inscription with a quote from Leviticus 25:10: >Proclaim liberty throughout all the land unto all the inhabitants thereof. My question is, what does that quote mean in its original context? Clearly, although it might have been the intent of the people who made the Liberty Bell, it did not mean "Spread the philosophy of classical liberalism to everyone", because liberalism is of course a doctrine that only born in the Enlightenment. So what does liberty mean in this passage? Does it mean freeing slaves or something?