Arcana Coelestia#8758
8758. 'And Israel encamped beside the mountain' means an arrangement effected by Divine heavenly good among those belonging to the spiritual Church. This is clear from the meaning of 'encamping' as an arrangement, as above in 8757; from the representation of 'Israel' as those who belong to the spiritual Church, also dealt with above, in 8751; and from the meaning of 'the mountain' as the good of heavenly love, dealt with in 4210, 6435, 8327. The words 'Divine heavenly good' are used to mean good from God as it exists in heaven; for that good as it exists in itself is far above heaven.
Arcana Coelestia#650
650. 'Length' means the holiness, 'breadth' the truth, and 'height' the good, of the remnants described by the numbers. This cannot be confirmed so easily from the Word because every single thing has reference to the particular subject or thing under discussion. For example, when 'length' applies to time it means perpetual and eternal, as in 'length of days' Psalms 23:6; 21:4, but when it applies to space it means consequent holiness. The situation is the same with 'breadth' and 'height'. All earthly objects are three-dimensional, but no such dimensions can be used in reference to celestial and spiritual things. When they are used to refer to these they mean the degree of perfection, greater or less, independent of the dimensions given, as well as identity and quantity. In this case they are identified as remnants, which are few in quantity.