“Be careful, or your hearts will be weighed down with dissipation, drunkenness and the anxieties of life, and that day will close on you unexpectedly like a trap. For it will come upon all those who live on the face of the whole earth. Be always on the watch, and pray that you may be able to escape all that is about to happen, and that you may be able to stand before the Son of Man.” - Luke 21:34-36
The Lord will come for his Church and then after a time of world-wide judgment he will return to set up his kingdom. Both occasions will occur unexpectedly for most. When people become preoccupied with the pleasures and anxieties of life, they tend to drift into their own little world. Thoughts of the Lord's coming slip away and they're unprepared for the unexpected.
Readings: OT Year 3 - Isaiah 56:1-57:13 / NT - Luke 22:14-30