Peter had used the word a moment earlier in relation to guilt. He now repeats the word in relation to innocence, that is, accepting the unjust penalty the master wrongly (in a moral sense; not legal) imposes upon you. The particular word Peter uses appears quite frequently throughout the New Testament in the sense of holding your ground, standing firm. The point is that you have followed your godly conscience and so offended your master by doing “good” (though that “good” was evil in his sight), and now you hold your ground even as you undergo a hard penalty, that is, your conscience remains clear before God in the midst of your suffering.
20 For what credit is it if, when you sin and are beaten for it, you endure? But if when you do good and suffer for it you endure, this is a gracious thing in the sight of God.