Of Jesus’ twelve apostles, which of them do you believe opened his mouth most often when he shouldn’t have? Nine out of ten people would probably all answer that the same: Peter! For a number of reasons, he has secured that 
reputation. Consider one instance in particular.
Peter, along with James and John, was on the mountain with Jesus, when the Savior was transfigured and spoke with Moses and Elijah. Peter, of course, quickly evaluated the situation (through his own eyes) and suggested building three tabernacles, one for each man, making Jesus to be equal with Moses and Elijah. Luke records that Peter said this, “not knowing what he said” (9:33). Mark records that Peter “did not know what to say” (9:6).
Are you ever like Peter? Do you ever say something when you shouldn’t? Do you ever just feel like something needs to be said, so you say something, even when you don’t know what to say? We would do well to remember, “He who has knowledge spares his words” (Prov. 17:27).