Deuteronomy 15:12 When thy brother is sold to thee, a Hebrew or a Hebrewess, and he hath served thee six years -- then in the seventh year thou dost send him away free from thee. (YLT)
Jeremiah 34:9 that every man should let his male servant, and every man his female servant, who is a Hebrew or a Hebrewess, go free; that none should make bondservants of them, to wit, of a Jew his brother. (WEB KJV ASV DBY WBS YLT)