4803. A matter wholly unknown in the world and worthy of mention is this: The states in which good spirits and angels live undergo constant change and perfection. In this way they are conveyed to the more internal parts of the province in which they dwell, and so into more excellent functions. For in heaven purification takes place constantly, which is so to speak a new creation. Yet the situation is that no angel to all eternity can possibly attain complete perfection. The Lord alone is the perfect One, He being the root and the source of all perfection. Those who correspond to the mouth constantly wish to be speaking, for speaking gives them utmost pleasure. While undergoing perfection they are restricted to speaking nothing but that which is beneficial to companions, the community, heaven, and the Lord. The delight they take in speaking in that way grows in the measure that the desire to regard themselves in what they speak and to strive after wisdom from what is properly their own passes away from them.
Arcana Coelestia #4803
Spiritual Experiences #668
668. Nevertheless, the state of mind of souls and angels changes as they are perfected, so they are transferred to better positions in the same member or province, in fact even to different provinces that are nobler. For there is a continual purification, and as I may call it, new creation, nor can ever any angel arrive at perfection itself, to eternity. The Lord Alone is Perfect, or Perfection Itself.