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.

8006. 'All the assembly of Israel shall keep it' means that this law of order is for all who are governed by the good of truth and guided by the truth of good. This is clear from the meaning of 'the assembly of Israel' as all truths and forms of good in their entirety, 7830, thus those who are guided by truth that leads to good, and governed by good through which truth comes, 7957, consequently those who belong to the spiritual Church. They were all required to keep the Passover in order that they might represent the deliverance of those belonging to the spiritual Church who were held back on the lower earth until the Lord's Coming, 6854, 6914, 7091 (end), 7849, 7932; and their eating it 'in one house' represented groups of angels living in association with one another in heaven, 7836, 7996, 7997, so that the keeping of it by the whole assembly of Israel represented the whole of heaven. At that time the Church did not exist anywhere, only a representative of the Church, for which Abraham's descendants through Jacob were selected. Through representatives of the Church contact with heaven was established, and through heaven with the Lord. This was why that nation was commanded to maintain a strict observance of all statutes and all laws, above all the statutes relating to the Passover, so strict that anyone who was clean and did not keep the Passover was to be cut off, Numbers 9:13.