From: Mark 8:34-9:1
Christian Renunciation (Continuation)
 And He (Jesus) called to Him the multitude with His disciples, and said to them, "If any man would come after Me, let him deny himself and take up his cross and follow Me.  For whoever would save his life will lose it; and whoever loses his life for My sake and the Gospel's will save it.  For what does it profit a man to gain the whole world and forfeit his life?  For what can a man give in return for his life?  For whoever is ashamed of Me and of My words in this adulterous and sinful generation, of him will the Son of Man also be ashamed, when He comes in the glory of His Father with the holy angels".
 And He said to them, "Truly, I say to you, there are some standing here who will not taste death before they see the Kingdom of God come with power."
35. "Life": in the original text and the New Vulgate the word literally means "soul." But here, as in many other cases, "soul" and "life" are equivalent. The word "life" is used, clearly, in a double sense: earthly life and eternal life, the life of man here on earth and man's eternal happiness in Heaven. Death can put an end to earthly life, but it cannot destroy eternal life (cf. Matthew 10:28), the life which can only be given by Him who brings the dead back to life.
Understood in this way, we can grasp the paradoxical meaning of our Lord's phrase: whoever wishes to save his (earthly) life will lose his (eternal) life. But whoever loses his (earthly) life for Me and the Gospel, will save his (eternal) life. What, then, does saving one's (earthly) life mean? It means living this life as if there were non other--letting oneself be controlled by the lust of the flesh and the lust of the eyes and the pride of life (cf. 1 John 2:16). And losing one's (earthly) life means mortifying, by continuous ascetical effort, this triple concupiscence--that is, taking up one's cross (verse 34)--and consequently seeking and savoring the things that are God's and not the things of the earth (cf. Colossians 3:1-2).
36-37. Jesus promises eternal life to those who are willing to lose earthly life for His sake. He has given us example: He is the Good Shepherd who lays down His life for His sheep (John 10:15); and He fulfilled in His own case what He said to the Apostles on the night before He died: "Greater love has no man than this that a man lay down his life for his friends" (John 15:13).
38. Each person's eternal destiny will be decided by Christ. He is the Judge who will come to judge the living and the dead (Matthew 16:27). The sentence will depend on how faithful each has been in keeping the Lord's commandments--to love God and to love one's neighbor, for God's sake. On that day Christ will not recognize as His disciple anyone who is ashamed to imitate Jesus' humility and example and follow the precepts of the Gospel for fear of displeasing the world or worldly people: he has failed to confess by his life the faith which he claims to hold. A Christian, then, should never be ashamed of the Gospel (Romans 1:16); he should never let himself be drawn away by the worldliness around him; rather he should exercise a decisive influence on his environment, counting on the help of God's grace. The first Christians changed the ancient pagan world. God's arm has not grown shorter since their time (cf. Isaiah 59:1). Cf. Matthew 10:32-33 and note on same.
1. The coming o the Kingdom of God with power does not seem to refer to the second, glorious coming of Jesus at the end of time (the Parousia); it may, rather, indicate the amazing spread of the Church in the lifetime of the Apostles. Many of those present here will witness this. The growth and spread of the Church in the world can be explained only by the divine power God gives to the mystical body of Christ. The Transfiguration of our Lord, which is recounted in the next passage, is a sign, given to the Apostles, of Jesus' divinity and of the divine powers which He will give His Church.
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.