Iniquity, transgression and sin
In the Word three terms are used to refer to bad actions: transgression, iniquity, and sin. Transgression is the least bad. It means a violation of what is true in an external context, a violation of what is right and orderly. Iniquity is next and denotes acts that violate more interior truths. Sin is the worst. It is a violation of what is holy and righteous, a violation against the Lord. Sin is the deepest kind of evil. Regarding iniquity -- to be in charity, or live a life of charity is to live a life where the acts and thoughts that have top priority are those that have within them a love for the neighbor. Sometimes our love of self, our inborn desire to put ourselves first, is stronger than our charity and we do something for ourselves at the expense of our neighbor, or even do harm to our neighbor. Such an act, if our motive is selfish, is an iniquity.
(Riferimenti: Arcana Coelestia 9156, 9965 [2-3])
Heaven and Hell #209
209. No influx is possible from the lower into the higher heavens because this is contrary to order, but there is influx from the higher heavens into the lower. Also the wisdom of the angels of a higher heaven surpasses the wisdom of the angels of a lower heaven, as a myriad to one. This is another reason that the angels of a lower heaven cannot speak with those of a higher heaven. In fact when they look towards them, they do not see them, the higher heaven appearing like a mist over their heads. Angels of a higher heaven, however, can see those in a lower heaven, but they are not allowed to talk with them on pain of losing their wisdom, as has been said above.