The thrust of 1 Peter 2:13-3:7 seems to be about living differently in existing relationships "for the Lord's sake" because we have been changed - note 2:13 "for the Lord's sake...", 3:1 "in the same way...", and 3:7 "in the same way...". Why muddy the waters by referring to the wife as weaker? In what sense does he mean "weaker"?