415. And I looked, and I heard an angel flying in the midst of heaven. (8:13) This symbolizes instruction and prediction from the Lord.

In the highest sense an angel means the Lord, and so also something from the Lord (no. 344). And to fly in the midst of heaven and speak means, symbolically, to perceive and understand, and when said of the Lord, to foresee and provide (no. 245). But here it means to instruct and predict.

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.