| Preach to the choir|
|Crux of the matter|
|Speak of the devil|
|An act of faith|
“”Whatever happens, they say afterwards, it must have been fate. People are always a little confused about this, as they are in the case of miracles.
|— Terry Pratchett, Interesting Times|
The idea of fate or destiny invokes the notion that some or all events are preordained by a god, a number of gods, muses, certain humans, or another force. Fate is an interesting superstition (or perhaps not a superstition) because like the mere existence of supernatural beings it can not be experimentally tested. That is to say anything that ever has happened, is now happening or ever will happen can be attributed to "fate" with no opportunity to disprove the claim. If there is such thing as fate, then free will may not exist, or will be severely weakened.
Fate is a common theme in narratives and plots, as it's either a convenient get-out clause for over-contrived plot-points or because it just makes things more interesting. Sometimes smart entrepreneurs use the mention of "fate" in woo such as fortune-telling to catch the imagination of listeners and to continue to talk them out of their money while the fortune-teller explains how all their dreams will inevitably come true and love is waiting around the corner, et cetera. This suggests some people supposedly can "read" the preordained future, so long as the readings remain sufficiently vague such that their claims can't be tested until long after the money is spent.
Religion-wise, peddlers of eschatology can go all out on the idea of doom (that which is "deemed" or fated) or destiny. If your name does not appear in the Book of Life... Hell, "Bishop" Brian Tamaki has even dubbed his self-created sect the "Destiny Church".