From: Luke 21:12-19
Discourse on the Destruction of Jerusalem and the End of the World (Continuation)
(Jesus said to His disciples),  "But before all this they will lay their hands on you and persecute you, delivering you up to the synagogues and prisons, and you will be brought before kings and governors for My name's sake.  This will be a time for you to bear testimony.  Settle it therefore in your minds, not to meditate beforehand how to answer;  for I will give you a mouth and wisdom, which none of your adversaries will be able to withstand or contradict.  You will be delivered up even by parents and brothers and kinsmen and friends, and some of you they will put to death;  you will be hated by all for My name's sake.  But not a hair of your head will perish.  By your endurance you will gain your lives."
19. Jesus foretells all kinds of persecution. Persecution itself is something inevitable: "all who desire to live a godly life in Christ Jesus will be persecuted" (2 Timothy 3:12). His disciples will have need to remember the Lord's warning at the Last Supper: "A servant is not greater than his master. If they persecuted Me, they will persecute you" (John 15:20). However, these persecutions are part of God's providence: they happen because He lets them happen, which He does in order to draw greater good out of them. Persecution provides Christians with an opportunity to bear witness to Christ; without it the blood of martyrs would not adorn the Church. Moreover, our Lord promises to give special help to those who suffer persecution, and He tells them not to be afraid: He will give them of His own wisdom to enable them to defend themselves; He will not permit a hair of their heads to perish, that is, even apparent misfortune and loss will be for them a beginning of Heaven.
From Jesus' words we can also deduce the obligation of every Christian to be ready to lose life rather than offend God. Only those will attain salvation who persevere until the end in faithfulness to the Lord. The three Synoptic Gospels locate His exhortation to perseverance in this discourse (cf. Matthew 24:13; Mark 13:13) and St. Matthew gives it elsewhere (Matthew 10:22) as does St. Peter (1 Peter 5:9)--all of which underlines the importance for every Christian of this warning from our Lord.
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.