From: Luke 12:35-38
The Need for Vigilance and the Parable of the Steward
(Jesus said to His disciples,)  "Let your loins be girded and your lamps burning,  and be like men who are waiting for their master to come home from the marriage feast, so that they may open to him at once when he comes and knocks.  Blessed are those servants whom the master finds awake when he comes; truly, I say to you, he will gird himself and have them sit at table, and he will come and serve them.  If he comes in the second watch, or in the third, and finds them so, blessed are those servants!"
35-39. In the preaching of Christ and of the Apostles we are frequently exhorted to be watchful (cf. Matthew 24:42; 25:13; Mark 14:34)--for one thing, because the enemy is always on the prowl (cf. 1 Peter 5:8), and also because a person in love is always awake (cf. Song of Songs 5:2). This watchfulness expresses itself in a spirit of prayer (cf. Luke 21:36; 1 Peter 4:7) and fortitude in faith (cf. 1 Corinthians 16:13). See the note on Matthew 25:1-13.
[The note on Matthew 25:1-13 states:
1-13. The main lesson of this parable has to do with the need to be on the alert: in practice, this means having the light of faith, which is kept alive with the oil of charity. Jewish weddings were held in the house of the bride's father. The virgins are young unmarried girls, bridesmaids who are in the bride's house waiting for the bridegroom to arrive. The parable centers on the attitude one should adopt up to the time when the bridegroom comes. In other words, it is not enough to know that one is "inside" the Kingdom, the Church: one has to be on the watch and be preparing for Christ's coming by doing good works.
This vigilance should be continuous and unflagging, because the devil is forever after us, prowling around "like a roaring lion, seeking someone to devour" (1 Peter 5:8). "Watch with the heart, watch with faith, watch with love, watch with charity, watch with good works [...]; make ready the lamps, make sure they do not go out [...], renew them with the inner oil of an upright conscience; then shall the Bridegroom enfold you in the embrace of His love and bring you into His banquet room, where your lamp can never be extinguished" (St. Augustine, "Sermon", 93).]
35. To enable them to do certain kinds of work the Jews used to hitch up the flowing garments they normally wore. "Girding your loins" immediately suggests a person getting ready for work, for effort, for a journey etc. (cf. Jeremiah 1:17; Ephesians 6:14; 1 Peter 1:13). Similarly, "having your lamps burning" indicates the sort of attitude a person should have who is on the watch or is waiting for someone's arrival.
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.