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.

482. Then I took the little book out of the angel's hand and ate it, and in my mouth it was as sweet as honey. (10:10) But when I had eaten it, my stomach became bitter. This symbolically means that so it came to pass, and thus it was shown, how this doctrine would be received before those people meant by the dragon, the beast, and the false prophet were removed.

Because this follows as a consequence from the aforesaid, it needs no further exposition.

We read that the prophet Ezekiel, too, was commanded to eat the scroll of a book, and that it was in his mouth as sweet as honey (Ezekiel 2:8-10; 3:1-3).