Jeremiah 34:14

At the end of seven years, in the so-called Sabbatical Year, let ye go every man his brother, an Hebrew, which hath been sold unto thee, rather, "who hath sold himself to thee"; and when he hath served thee six years, thou shalt let him go free from thee; Cf Exodus 21:2; Deuteronomy 15:12. But your fathers hearkened not unto Me, neither inclined their ear, they paid not the slightest attention to His command.