It is common in the Bible for people to "rise up," and it would be easy to pass over the phrase as simply describing a physical action. But in fact it represents an elevation in spiritual state, moving to a more internal frame of mind closer to the Lord. Often it has to do with understanding a new or important idea; we "rise up" to a state of greater perception and enlightenment. Obviously context is crucial to the exact meaning of the phrase in a given passage -- it matters greatly who it is that is rising up, and why.

2850. 'And like the sand which is on the seashore' means a whole multitude of correspondent facts. This is clear from the meaning of 'the sea' as facts in general or a gathering together of them, dealt with in 28, 2120, and from the meaning of 'the sand' as facts individually and separately. Facts are compared to 'the sand' because in the internal sense the particles of stone from which the sand is formed mean facts, 643, 1298. Both comparisons are made here - that they will be multiplied 'as the stars of the heavens' and 'as the sand on the seashore 'because 'stars', or cognitions, are related to the rational, whereas 'the sand of the seashore', or facts, are related to the natural. When the things that belong to the rational man, namely the goods and truths present in cognitions, so exist in accordance with the things that belong to the natural man, that is to say, with facts, that they make one or mutually support each other, they in that case correspond. The Lord brings man's rational concepts and his natural images into this state of correspondence when He regenerates him, that is, makes him spiritual. It is for this reason that both the stars of the heavens and the sand on the seashore are mentioned here. Otherwise one phrase would have been sufficient.