From: Luke 21:34-36
The Need for Vigilance
(Jesus said to His disciples),  "But take heed to yourselves lest your hearts be weighed down with dissipation and drunkenness and cares of this life, and that day come upon you suddenly like a snare;  for it will come upon all who dwell upon the face of the whole earth.  But watch at all times, praying that you may have strength to escape all these things that will take place, and to stand before the Son of Man."
34-36. At the end of His discourse Jesus emphasizes that every Christian needs to be vigilant: we do not know the day nor the hour in which He will ask us to render an account of our lives. Therefore, we must at all times be trying to do God's will, so that death, whenever it comes, will find us ready. For those who act in this way, sudden death never takes them by surprise. As St. Paul recommends: "You are not in darkness, brethren, for that day to surprise you like a thief" (1 Thessalonians 5:4). Vigilance consists in making a constant effort not to be attached to the things of this world (the concupiscence of the flesh, the concupiscence of the eyes and pride of life: cf. John 2:16) and in being assiduous in prayer, which keeps us close to God. If we live in this way, the day we die will be a day of joy and not of terror, for with God's help our vigilance will mean that our souls are ready to receive the visit of our Lord; they are in the state of grace: in meeting Christ we will not be meeting a judge who will find us guilty; instead He will embrace us and lead us into the house of His Father to remain there forever. "Does your soul not burn with the desire to make your Father-God happy when He has to judge you?" ([St] J. Escriva, "The Way", 746).
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.