What do the words “mindful of God” mean?

The phrase mindful of God could more literally be rendered as “through a godly conscience.” The translation rests on understanding this phrase to mean that Peter would have the oppressed slave draw strength from God’s promises. Yet the Greek does not allow that interpretation (though, of course, it’s doctrinally true). Peter would have the slaves remember that even in slavery they are responsible before God for their conduct and so cannot blindly do everything their masters demand. A clear example is Joseph’s response to Potiphar’s wife: “How can I do this great wickedness and sin against God?” (Genesis 39:9). Because of his godly conscience he continually refused her advances (1 Peter 2:10) and when she sought to force him, he hastily shrugged out of the garment she had grabbed and fled (1 Peter 2:12)—no matter the predictable consequences.