One of the reasons Scripture scholars prefer to talk about "the Scriptures" and avoid using the term "the Bible' revolves around their realization that our sacred writings are actually a library, not a book.
Walking into a library, most of us quickly grasp the obvious: a library is a collection of books, written at different times and places by different authors. But notice the signs displayed above the various shelves: fiction, biography, poetry, history, reference, etc. Each section of the library offers a different "literary genre;" a different style or form of writing which the authors have chosen to convey their message.
Only by first recognizing a writer's genre can we eventually understand the writer's message. Poets, for instance, can have animals and the wind talk, something biographers can't do. Novelists can describe in great detail a person's innermost thoughts, something a historian can only speculate about.
The literary genre of today's first and third readings is apocalyptic. This form of writing normally originates during periods of persecution, when people find it difficult to concentrate on the pain their present situation brings. Apocalyptic authors focus their readers' eyes on the future, describing the salvation God has promised to provide, all the time making certain their readers also understand the "cosmic" significance of the suffering they're enduring. Their distress isn't being ignored by God; on the contrary, God is using it to bring about a future in which the just will no longer suffer such anguish.
Apocalyptic writers often predict events which have already happened years before they write. Though such a practice causes historical authors to cringes, it's as much a part of this genre as a farmer's scarecrow speaking to someone in a line of poetry.
Today's Daniel reading, for instance, was composed several centuries after the Babylonian Exile it describes, during the Seleucid persecution of the Jews. By making it appear it was written in the 6th century BCE instead of the 2nd century BCE, the sacred author is conveying the message that just as Yahweh delivered the Chosen People back then, so Yahweh will take care of them now, even if that care might not be evident until those people step into eternity. (It's significant that this passage contains the earliest biblical reference to heaven: "Some shall live forever . . . .")
Mark's apocalyptic pericope seems to have been triggered not so much by an actual persecution as by a general fear that persecutions were just around the corner for Jesus' disciples. Employing the commonly accepted idea of how the world would one day end, the evangelist wants his people to understand that, no matter what, Jesus will be present, guiding and protecting "his chosen" from the distress others will experience. They should stop worrying about the unknown, painful future, and put their trust and confidence in Jesus. That's why he ends this section with Jesus' words, "As to the exact day or hour, no one knows it, neither the angels in heaven not even the Son, but only the Father." In other words, don't let your fear of something you can't control stop you from doing the things you can control.
After all, the Hebrews author tells us, no matter what the future holds, the most important thing has already been taken care of. "Jesus offered one sacrifice for sins and took his seat forever at the right hand of God . . . . By one offering he has forever perfected those who are being sanctified."
Whatever genre our sacred authors employ, the Scriptures they produce consistently remind us both of what God has already done for us, and what we are expected to do because of those actions.