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.

1176. That 'Cush begot Nimrod' means that those who had cognitions of interior things were the instigators of such worship is clear from what has just been stated. Cognitions of interior things are what they call matters of doctrine, which they also distinguish from ritual forms. For example, their chief point of doctrine is that faith alone saves, but they are not aware of the fact that love to the Lord and love towards the neighbour constitute faith itself, and that the cognitions which they call faith exist for no other purpose than that through them people may receive from the Lord love to Him and love towards the neighbour, and that this is the faith which saves. Those who refer to cognitions alone as faith are the people who beget and instigate the kind of worship described above.