21:1-11 The laws in this chapter relate to the fifth and sixth commandments; and though they differ from our times and customs, nor are they binding on us, yet they explain the moral law, and the rules of natural justice. The servant, in the state of servitude, was an emblem of that state of bondage to sin, Satan, and the law, which man is brought into by robbing God of his glory, by the transgression of his precepts. Likewise in being made free, he was an emblem of that liberty wherewith Christ, the Son of God, makes free from bondage his people, who are free indeed; and made so freely, without money and without price, of free grace.

Ex 21:7-36. Laws for Maidservants.

7-11. if a man sell his daughter—Hebrew girls might be redeemed for a reasonable sum. But in the event of her parents or friends being unable to pay the redemption money, her owner was not at liberty to sell her elsewhere. Should she have been betrothed to him or his son, and either change their minds, a maintenance must be provided for her suitable to her condition as his intended wife, or her freedom instantly granted.