Exodus 21:2

'If you buy a Hebrew servant, he is to serve you for six years. But in the seventh year, he shall go free, without paying anything.

(New International Version)

'If you buy a Hebrew slave, he shall serve for six years; but on the seventh he shall go out as a free man without payment.

(New American Standard Bible)

If thou buy an Hebrew servant, six years he shall serve: and in the seventh he shall go out free for nothing.

(King James Version)