In most cases, "mouth" in the Bible represents thought and logic, especially the kind of active, concrete thought that is connected with speech. The reason for this is pretty obvious, but it also holds when people, for instance, remove a stone from the mouth of a well, which represents gaining access to spiritual ideas. The mouth is used for eating as well as speaking, of course. In those circumstances, it represents our first, most external perception of a new spiritual idea or desire. This also makes sense, mirroring the way tasting food in the mouth gives us an instant impression of the quality of the food.

91. From the human face it can be seen what correspondence is. In a face that has not been taught to dissemble, all the affections of the mind present themselves to view in a natural form, as in their type. This is why the face is called the index of the mind; that is, it is man's spiritual world presented in his natural world. So, too, what pertains to the understanding is presented in speech, and what pertains to the will is presented in the movements of the body. So whatever effects are produced in the body, whether in the face, in speech, or in bodily movements, are called correspondences.