The mind is the guardian of memories and fantasies, the past and the future respectively. Memories and fantasies come in two (and only two) varieties: good and bad. This means that all desires (related to keeping good memories and creating good fantasies) and all fears (related to avoiding bad memories and bad fantasies) come within the jurisdiction of the mind.
Unfortunately for the mind, the present moment is the only moment that is, in any sense, real. Moreover, in spiritual terms, the present moment is the only possible occasion in which we can meet God (or anyone else).
From Bread & Water, Wine & Oil by Archimandrite Meletios Webber (20).
“Does it hurt?” asked the Rabbit.
“Sometimes,” said the Skin Horse, for he was always truthful. “When you are Real you don’t mind being hurt.”
“Does it happen all at once, like being wound up,” he asked, “or bit by bit?”
“It doesn’t happen all at once,” said the Skin Horse. “You become. It takes a long time. That’s why it doesn’t often happen to people who break easily, or have sharp edges, or who have to be carefully kept. Generally, by the time you are Real, most of your hair has been loved off, and your eyes drop out and you get loose in the joints and very shabby. But these things don’t matter at all, because once you are Real you can’t be ugly, except to people who don’t understand.”
From The Velveteen Rabbit by Margery Williams.