...Jesus is a recurring character, because FCC rules stipulate you cannot use "Jesus Christ" as an exclamation unless the deity himself is present...Aside from being out right funny, it explains a couple times where Peter has said things like "Jesus Christ" and then after a pause the camera angle has turned and Jesus has been in the scene.
Oh FCC you never fail to amaze me
Fast Company's article "Seth MacFarlane’s $2 Billion Family Guy Empire" highlights some interesting subtleties in the FCC rules for indecency: