There are really two meanings for "build" in the Bible. When something is being built for the first time, or built in the most typical sense, it means collecting relatively external ideas to build up a doctrinal system. In other cases, though, "build" is used in reference to something that has been destroyed. In such cases, "build" refers to removing our desires for evil so we can began a new stage of spiritual growth. In these cases "build" is often used together with "raise up," which means removing false ways of thinking in the same process.

(Odkazy: Arcana Coelestia 153, 1488, 4390)

6648. 'And multiplied and became very very numerous' means that they increased enormously in truths from good. This is clear from the meaning of 'multiplying' as increasing in truths, dealt with in 43, 55, 913, 983, 2846, 2847; and from the meaning of 'became numerous' as further branching out, thus a constant increase in truth. The reason why it is an increase in truth from good is that the subject now is the Church when it has been established. For so far as the establishment of the Church with a person is concerned, it happens as follows: While it is being established the person is governed by truths, and through them good increases. But once the Church has been established with him he is governed by good, and from good by truths, which are then constantly increasing. Little increase takes place while he lives in the world, because in the world concerns about food and clothing and about other matters prevent it. But in the next life the increase is vast, and goes on for evermore; for there is no end to wisdom from the Divine. In this way the angels are constantly being made more perfect, and in that same way all entering the next life are made into angels; for every aspect of wisdom is capable of infinite expansion and the aspects of wisdom are infinite in number. From this it may be seen that wisdom can go on increasing for evermore and still not reach very far beyond the first degree, the reason for this being that the Divine is the Infinite, and what has its origin in the Infinite is inevitably like that.