A little more on the previous theme.
The self fears annihilation above all else. But what does Christ promise first and foremost but the total annihilation of everything contrary to the will and glory of God within us? He promises that it will be gradual and bearable, but eventually complete and all encompassing. The fear, then, comes from the self having knowledge of his own demise. We anticipate the things we hold most dear being systematically demolished by the One we hold most dear. The part of us that fears, the mortal part, is slated for execution, and he knows it, and he is determined not to go quietly into that good night.
Psychological pain is one thing that sets we humans apart from what Aristotle called ‘the balance of the animal economy’. A dog suffers when it it struck, but since it’s capacity for language and reason are limited, it can’t anticipate events in the future; but just tell someone you’re going to hit them and they will suffer, even though you haven’t done anything. A person’s status as res cogiton ensures that knowledge of future suffering can be as bad as the suffering itself.
“I’m going to give you a cookie tomorrow” yields a momentary smile, laugh, or feeling of well being. But “I’m going to hit you tomorrow” is much more disruptive. Hope isn’t as potent as dread, I think. Or perhaps it is, but only after one has trained oneself, and taken one’s thoughts wholly captive. For what better news can we get than “Someday, and it might be very soon, you will say goodbye to all pain, fear, and suffering, and assume your role as a beloved child of God, basking in His loving presence forever”? But it’s disrupted so easily that if we don’t meditate on it constantly, it’s quickly forgotten.