The Jubilee in the Old Testament
The Sabbatical Year
The Jubilee Year
How it was Practiced
The Jubilee Year

The Jubilee Year represented a certain perfection of the Sabbath Year legislation. It provided for a double portion of rest every 50th year. Each 49th year would be a Sabbath Year, followed by a Jubilee Year in the 50th, so that for two consecutive years the people would be bound to restore the land, personal and economic freedom and to depend on God.

8 And you shall count seven weeks of years, seven times seven years, so that the time of the seven weeks of years shall be to you forty-nine years. 9 Then you shall send abroad the loud trumpet on the tenth day of the seventh month; on the day of atonement you shall send abroad the trumpet throughout all your land. [the Day of Atonement - 10th day of Tishri - was the day on which sin was expiated] 10 And you shall hallow the fiftieth year, and proclaim liberty throughout the land to all its inhabitants; it shall be a jubilee for you, when each of you shall return to his property and each of you shall return to his family. 11 A jubilee shall that fiftieth year be to you; in it you shall neither sow, nor reap what grows of itself, nor gather the grapes from the undressed vines. 12 For it is a jubilee; it shall be holy to you; you shall eat what it yields out of the field. 13 In this year of jubilee each of you shall return to his property.

We can also gain some insight into the idea of the Jubilee from the name itself. It seems to be named after the sound produced by the trumpets announcing a feast day, in this case the Day of Atonement on which the Jubilee Year began. Such horns were used to announce the presence of a great personage and to call an assembly. The most common name for such a trumpet was shopar (ram’s horn). Less commonly, it was called yobel. This perhaps refers to the joyfulness of the sound (what in literature is called "onomatopoeia" - a word which mimics the sound it represents). Similar words exist in other languages, such as the German yodel (a crying out). 

In summary, the Jubilee Year was intended to be a joyful celebration of God’s sovereignty in which for His People there was:

1) Emancipation: Redeemed by God, no Israelite can forever remain a slave. The Jubilee was meant to restore equality among the Israelites

2) Social Justice: Equality meant raising up, as well, those who were in need. God’s Providence is for all, so the goods of the earth are the common property are all.