"Hallow the fiftieth year and proclaim liberation in the land for all its inhabitants."
When the Lord spoke to Moses on Mount Sinai he told him to say to the Israelites: When you enter the land which I am giving you, the land must keep sabbath to the Lord. For six years you may sow your fields and prune your vineyards and gather the harvest, but in the seventh year the land is to have a sabbatical rest, a sabbath to the Lord. You are not to sow your field or prune your vineyard; you are not to harvest the crop that grows from fallen grain, or gather in the grapes from the unpruned vines. It is to be a year of rest for the land. Yet what the land itself produces in the sabbath year will be food for you, for your male and female slaves, for your hired man, and for the stranger lodging under your roof, for your cattle and for the wild animals in your country. Everything it produces may be used for food.
You are to count of seven sabbaths of years, that is seven times seven years, forty-nine years, and in the seventh month on the tenth day of the month, on the Day of Atonement, you are to send the ream's horn throughout your land to sound a blast. Hallow the fiftieth year and proclaim liberation in the land for all its inhabitants. It is to be a jubilee year for you; each of you is to return to his holding, everyone to his family. the fiftieth year is to be a jubilee year for you; you are not to sow, and you not to harvest the self-sown crop, or gather in the grapes from the unpruned vines, for it is a jubilee, to be kept holy by you. You are to eat the direct produce from the land.
In the year of jubilee every one of you is to return to his holding. When you sell or buy land amongst yourselves, neither party must exploit the other.
You must pay your fellow countryman according to the number of years since the jubilee, and he must sell to you according to the remaining number of annual crops. The more years there are to run, the higher the price; the fewer the years, the lower, because what he is selling you is a series of crops. You must not victimize one another, but fear your God, because I am the Lord your God. Observe my statutes, keep my judgments, and carry them out; and you will live without fear in the land. The land will yield its harvest; you will eat your fill and live there secure. If you ask what you are to eat during the seventh year, seeing that you will neither sow nor gather the harvest, I shall ordain my blessing for you in the six year and the land will produce a crop sufficient for three years. When you sow in the eighth year you will still be eating from the earlier crop; you will eat the old until the new crop is gathered in the ninth.
Leviticus 25:1-22, REB.
From what I remember about this passage from seminary, there is no evidence Israel ever observed a jubilee year; I'm not even sure they observed a seventh year. After the exile the law of Moses was re-written by the Deuteronomist school (the word itself is Greek, roughly translating as "second law." Lawyers might call it the "restatement" of the law, which would be more accurate). However, my analytical concordance indicates there is no presence of the word "jubilee" outside of Leviticus, save for Numbers 36:4: "When the jubilee year comes around in Israel, her share would be added to the share of the tribe into which she marries, and it would be permanently lost to the portion of our father's tribe." A few verses later, the book of Deuteronomy begins.
It's obviously a law meant for a group; not for modern nations or modern societies. What might Israel have been, however, had they tried? What might it do for the world, if the world tried?