In Exodus 11:5, 'the servant-girl behind the mill' [signifies] the most external affection for knowledge, since 'behind the mill' means that which occupies the very last place. The expression 'behind the mill' is used because 'the mill' has reference to matters of faith. For by means of a mill, grain is ground into flour and so prepared for making bread, and 'flour' means truth which results in good, 'bread' the actual good that results from it. Thus 'sitting at the mill' is acquiring and learning the kinds of things that will be of service to faith, and through faith of service to charity. This is why when the ancients described learning the basic elements of faith they described it as 'sitting at the mill', or learning elements even more basic as 'sitting behind the mill'. (Arcana Coelestia 7780)

6923. On another occasion I saw a great number of that kind of spirits, but these were some distance away out in front, slightly to the right. They talked to me from there, but they did so with the help of intermediary spirits; for their speech, flowing as fast as thought, cannot be converted into human language without the help of intermediary spirits. And what surprised me, their words were full and rounded even though they spoke all together and yet with no less promptness and speed. Their speech sounded to me like a wave because there was a large number of them speaking simultaneously; and what was remarkable, it made its way towards my left eye even though those spirits were on the right. The reason for this was that the left eye corresponds to knowledge of things separated from their material associations, thus things that belong to intelligence, whereas the right eye corresponds to things that belong to wisdom. Displaying the same promptness as they did when speaking those spirits also perceived and formed judgements of the things they heard, saying, This is so, that is not so. Those judgements were formed by them almost instantaneously.