EVEN though things keep happening in sequence and progressing in heaven the way they do in the world, still angels have no notion or concept of time and space. The lack is so complete that they simply do not know what time and space are. Here we will discuss time in heaven, leaving space to be discussed in its own chapter.
The reason angels do not know what time is (even though everything for them moves along in sequence just the way it does in our world, so much so that there is no difference) is that in heaven there are no years or days, but only changes of state. Where there are years and days there are times, and where there are changes of state, there are states.
The reason we have times in our world is that the sun seems to move sequentially from one zone to another and to make the times we call the seasons of the year. It also moves around the earth and makes the times we call times of day, and it does these by fixed periods. It is different for heaven’s sun. It does not make years and days by sequential motions and rotations, but makes apparent changes of state; and it does not make these by fixed periods, as explained in the preceding chapter. This is why angels are incapable of having any concept of time, but have a concept of state instead. What “state” is may be seen above in Section 154.
from Heaven and Hell, Sections 162-164