Thom Rainer lists eight things that distract a pastor while he is teaching along with a rude example. #8 on his list is cell phones ringing. He says that today we usually ask for all phones to be silenced before the service begins, so it's not as bad as it used to be. However, he once did a funeral when the deceased's son's phone rang and he actually started talking to his hunting buddy while he continued his message." Very rude to talk on a cell phone in church. If you must take the call, leave so that they rest of us are not distracted by you.