And many of them used that portion of Exodus immediately following the Ten Commandments as justification in that belief. 

Starting at Exodus Chapter 20, "If you buy a Hebrew servant..."  and into the New Testament where Paul the Apostle returns a runaway slave called Onesimus to the slave-master Philemon. This slave found his way to the site of Paul's imprisonment (most probably Rome or Caesarea) to escape punishment for a theft of which he was accused. Epistle to Philemon 1:10–16