Like most numbers in the Bible, "six" can have various meanings depending on context, but has a couple that are primary. When used in relation to time -- six days, six hours, six years, etc. -- six generally represents a state of labor, struggle and conflict, especially the conflict involved with spiritual growth. The six days of creation, for instance, represent the stages we go through in our lives, working toward the peaceful seventh day, in which our evil desires are removed from us and we can rest. In most other references, six represents all desires for good and all the true ideas that come from those desires for good -- or in the contrary sense, all evil and all the resulting false thinking.

59. Unto Ephesus, and Smyrna, and Pergamum, and Thyatira, and Sardis, and Philadelphia, and Laodicea, signifies in each case according to reception. This is evident from what follows, where these churches are treated of in detail. It is said according to reception, because the light of intelligence does not constitute the church with man, but the reception of light in heat, that is, the reception of truth in good. It is said the reception of light in heat, because spiritual light is Divine truth, and spiritual heat is Divine good, and these two in the spiritual world are as light and heat in the natural world; for insofar as spring or summer heat is added to the light, so far all things grow and germinate, but so far as that heat is not added to the light, so far all things become torpid and die. (That light in the spiritual world is Divine truth, and heat there is Divine good, and that they are as heat and light in the natural world, see the work on Heaven and Hell 126-140.)