Remember that the “end” spoken of in verse 14 is not the end of all things, but the end of the Old Testament era, the destruction of Jerusalem and the Temple (including the sacrificial system) in the years surrounding 70AD.
The “Abomination of Desolation” was the desecration of the Temple by the Romans. Jerusalem was surrounded by the Romans, but then the Romans left for a time before they came back to destroy the city and Temple; hence the warnings. Compare this with the parallel in Luke 21:20-22: 20 “But when you see Jerusalem surrounded by armies, then recognize that her desolation is at hand. 21 “Then let those who are in Judea flee to the mountains, and let those who are in the midst of the city depart, and let not those who are in the country enter the city; 22 because these are days of vengeance, in order that all things which are written may be fulfilled.”
Christ’s return to judge the generation which rejected and crucified Him, like lightning flashing across the sky from east to west, would be evident to all. Therefore one could discount all accounts of the presence of the Messiah anywhere else.
In verses following our selection He will give indications that the event is very near (in time). Until then our duty is to remain faithful to Him. That means being in His Word often so that we know how to obey, and spending time often with Him in prayer so that we can obey.