There are some numbers that are used with such frequency in the Bible — numbers like seven, 12 and 40 — that it is clear that they have special significance. In Swedenborg, those numbers tend to have well-defined and consistent inner meanings. Seven shows holiness; 12 shows completeness; and 40 shows states of deep temptation and spiritual struggle.
Other numbers tend to be more fluid in their meaning, affected by context. The number 15 is a good example of that. Swedenborg offers three primary meanings: “things so few as to be scarcely anything at all” in the story of the Great Flood, “a sufficient amount” when it is used in descriptions of the Tabernacle, and as a beginning state when it is used as a measurement of time (“the fifteenth day of the month). Obviously different things are being measured in each case, which affects the meaning, and the number 15 can also be arrived at in different ways. In discussing the flood, Swedenborg looks at it as the sum of 10 and five, for instance, and in the measurement of time considers it as one more than 14.
Passages from Swedenborg
Arcana Coelestia (Elliott) n. 798
798. ‘From fifteen cubits upwards the waters prevailed and covered the mountains’ means that no trace of charity remained; and ‘fifteen’ means things so few as to be scarcely any at all. This becomes clear from the meaning of the number ‘five’, dealt with in Chapter 6:15. There it was shown that in the style of the Word, that is, in the internal sense, ‘five’ means those that are few. And since the number fifteen is the sum of five, which means few, and of ten, which means remnants, as has been shown at 6:3, this number has regard to remnants, which with those people were hardly anything at all. For so great were the persuasions of falsity that they did away with everything good. With regard to the remnants residing with man, the false assumptions, as stated already, and still more the persuasions of falsity, were of such a nature with the people before the Flood that they shut in and shut away remnants so completely that they could not be brought out. And if they had been brought out they would have been falsified in an instant. Indeed the life inherent in persuasions is such that it not only rejects everything true and soaks up everything false, but also perverts any truth that goes near it.
Arcana Coelestia (Elliott) n. 9760
9760. ‘And hangings of fifteen cubits shall there be for [one] wing’ means the sufficient quantity of truths dwelling in light. This is clear from the meaning of ‘fifteen’ as a sufficient amount; from the meaning of ‘the hangings’ as truths, dealt with above in 9743; and from the meaning of ‘wing’ as the place where truths dwell in light. The reason why [this] wing has this meaning is that ‘wing’ describes one part of the breadth of the court on the east side. For the breadth of the court was fifty cubits, in the middle of which was the gate with a screen twenty cubits wide, verse 16. The two parts, one to the right of the gate and the other to the left, are called wings, the hangings for each being fifteen cubits, so that the full breadth, as stated, was fifty cubits. It is evident therefore that one wing extended towards the south, but the other towards the north, so that by ‘the hangings’ of the wing extending towards the south truths dwelling in light are meant (‘the south’ being where truth dwells in light, 9642), and by ‘the hangings’ of the wing extending towards the north, which the next verse refers to, truths dwelling in obscurity are meant (‘the north’ being where truth dwells in obscurity, 3708).
Arcana Coelestia (Elliott) n. 8400
8400. ‘On the fifteenth day of the second month’ means this state considered in relation … This is clear from the meaning of the number ‘fifteen’, from the meaning of ‘day’, and from the meaning of ‘month’. ‘Month’ means the end of the previous state and the beginning of the next, thus a new state, 3814; ‘day’ means a state in general, 23, 487, 488, 493, 893, 2788, 3462, 3785, 4850, 7680, and ‘the fifteenth’ means that which is new. For ‘fourteen days’ or two weeks mean a whole period or state from the beginning to the end of it, 728, 2044, 3845; ‘fifteen’ therefore means something new, in this instance newness of life, meant by the manna which they received from heaven, ‘manna’ being the good of truth, which is the life of a spiritual person. Fifteen is similar in meaning to eight, because the eighth day is the first day of a following week. For the meaning of ‘the eighth day’ as any beginning whatever, thus something new that is distinct and separate from what has gone before, see 2044, 2866; and for the fact that all numbers in the Word have spiritual realities as their meaning, 482, 487, 575, 647, 648, 755, 813, 1963, 1988, 2075, 2252, 3252, 4264, 4495, 4670, 5265, 6175.
Arcana Coelestia (Elliott) n. 813
813. That these words mean the point at which the Most Ancient Church finally came to an end, and that ‘a hundred and fifty’ means that which is both a finishing point and a starting point, cannot be confirmed so easily from the Word as the more simple numbers can which occur frequently. Nevertheless the matter is clear from the number fifteen, dealt with above at verse 20. Fifteen means so few as to be hardly any. This meaning applies all the more to the number ‘a hundred and fifty’, which is the product of fifteen multiplied by ten, which means remnants. Multiplying fractions, such as a half, a quarter, or a tenth, produces smaller fractions still, till at length there is practically nothing, and then the end or finishing point has been reached. The same number occurs in Chapter 8:3 below where it is said that the waters retreated at the end of a hundred and fifty days. There the meaning is similar. Numbers in the Word have to be understood abstractedly – quite apart from the sense of the letter, for as stated and shown already, they have been included merely to produce the flow of historical events that belongs to the sense of the letter. For example, when seven occurs it means that which is holy – quite abstractedly from periods of time or measurements which it is normally used to quantify. Indeed angels, who perceive the internal sense of the Word, know nothing whatever about periods of time or measurements, let alone what a specific number denotes. Yet they understand the Word completely when it is being read by man. Consequently when a number occurs anywhere at all they cannot possibly have the idea of any numerical value, only of the real thing meant by the number. Likewise in the present context they understand by this number the point at which the Most Ancient Church finally came to an end, and in verse 3 of the next chapter the starting point of the Ancient or new Church.