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.

In Genesis 26, the well signifies that people who were in the mere worldly knowledge of truths of faith were unwilling to make the internal nature of the Divine more well-known. (Arcana Coelestia 3412)

Broken cisterns in Jeremiah 2:13 signify false doctrines.

In Deuteronomy 6:11, cisterns hewn out signify the interiors of the natural mind–full of knowledge of good and truth. (Apocalypse Explained 617[13])

(Odkazy: Arcana Coelestia 2702 [1-17])