It is important to remember that each of the gospels was written at different times to a particular audience with a special emphasis due to circumstances of place and time. Tradition has it that Mark’s Gospel was written for the people in Rome under the influence of Peter. Mark’s was the first Gospel to develop, and was written about 30 years after the crucifixion of Jesus and around the time of the Roman destruction of Jerusalem and the Temple.
Mark’s gospel emphasizes discipleship and its cost. To believe in Jesus and to be found in his company means to take serious the words of Jesus to deny one’s very self, to take up the cross and follow Him (8:34). It means to realize how to save one’s life is to lose it and to lose one’s life for the sake of the gospel is to find it (8:35-37). In a Gospel where there is continual motion, the cross and resurrection are the climax of the story of Jesus. Everything Jesus said and did led up to His passion.
And just as for Jesus, so for His followers. The way of the cross is their path too. Its pain and trial is the only way to glory. Jesus leads His disciples to accept the demands of the cross. Jesus teaches the disciples how they are to differ radically from others in their society and culture. They are not to act on ambition and seek after power but, like Jesus, they are to be those who serve, attentive especially to those in misery and need. For Mark, there is no safe and easy way to be a follower of Jesus, the Crucified One.
Unlike Matthew or Luke, Mark does not provide us with "the euphoria of the infancy narratives." He begins abruptly and bluntly with John the Baptist in the desert shouting that there is "one mightier than I in your midst who will baptize you in the Holy Spirit."
Then just as starkly, Jesus appears to be baptized (1:9-11) and immediately is sent into the wilderness to be tempted and to face the dangers of wild animals (1:12-13).
Almost immediately, the one who had prepared the way for Jesus is thrown into prison (1:14). Jesus picks up exactly where John left off except that His message is that the time has arrived what John said was on the horizon. Jesus appears in Galilee proclaiming the good news of God saying, "This is the time of fulfillment… The reign of God is at hand. Turn your lives around. Believe in the gospel." As the gospel develops we read how, just as John was faithful to his calling and arrested for it, so Jesus remains true to His calling and is crucified by those who oppose Him. Following His death, an angel appears to the women who visit His tomb after his resurrection and tells them "Go now and tell the disciples and Peter, ‘He is going ahead of you to Galilee where you will see him as he told you.’" If one accepts the shorter ending of Mark, Jesus’ mission and ministry begins and ends in Galilee and ends with a degree of uncertainty.
There is considerable debate over the textual evidence regarding the ending of Mark. The earliest manuscripts of Mark end with 16:8 with the words "they were afraid."  The women fail to follow the instructions of the heavenly messenger, giving an ambiguous ending to the Gospel. We are left to wonder, "What of the disciples? Will they obey His instructions?" If we accept the shorter ending as being the Mark's intended one, he ends at the brink of a new beginning, but we are left to wonder whether it will really happen. The Gospel had started with John the Baptist pointing the way to Jesus and ends with the women refusing to tell others about Him because of fear.
It should be noted that the discussion that follows is not dependent upon the reader accepting the "shorter" ending of Mark. As we shall discover below, the actions of the women in 16:8 are consistent with the way in which Mark depicts the disciples in his gospel. The descriptions of the disciples in the verses that appear in later manuscripts (16:9-20) are hardly more flattering. The fear that marked the women is matched by the doubt exhibited by the disciples. The disciples consistently do not believe (16:11, 13). Jesus rebukes them for their lack of faith and refusal to believe the testimonies of those who had witnessed His resurrection (16:14). It is worth noting that this is also consistent with how Christians throughout history (and even to the present day) respond to persecution. Some believe, others are afraid and say nothing, while others leave the Christian fellowship entirely.
Of all of the Gospel writers, Mark is, by far, the one who best reveals the failings of the disciples. Peter, for example, called Jesus the Messiah, but promptly revealed that he had no idea what that meant, having his own ideas about what it meant to the anointed one of God and how Jesus should live that out. He is rebuked as being "Satan", an adversary (8:33). Peter had to learn through experiences of failure, dismay and even denial the real meaning of Messiah.
The other disciples are likewise depicted rather poorly in Mark’s Gospel. They start off so well. At first the ones who oppose Him are His family (3:21, 31-34) and the teachers of the law (3:22-30). Jesus recognized that not everyone would accept His teaching (the Parable of the Soils in 4:1-24) and that some will fall away under persecution (4:17).
The disciples are viewed relatively positively until 6:30, even though there are difficulties (e.g. 4:13; 4:38; 5:31). But following each incident, Jesus instructs them and the problem appears to have been resolved. But as time goes on, it is clear that they do not understand who Jesus really is. Time and again they do not grasp the meaning of what He said (4:13; 6:51-52; 7:18; 8:18, 21; 8:32-33; 9:32). They fail to cast out a demon because of their lack of faith and prayer (9:19, 29). They try to chase away those who try to bring children to Jesus (10:13-14). They treat Jesus as if He were naïve (4:38; 5:31; 6:37). They quarrel over who is the greatest (9:33-36) and jockey for position (10:35-41). They forbid others not in their group to use Jesus’ name (9:38). Jesus begins to see a hardness in their hearts not unlike that demonstrated by His enemies (compare 3:5-6 with 6:52 and 8:17). Jesus questions whether they are capable of seeing and hearing (8:18) in a context where He has healed a deaf and blind man (7:31-37, 8:22-26). The three boat scenes depict the disciples as fearful, distrustful of Jesus and self-concerned (4:40, 6:49-50, 8:14-16). They fall asleep in the garden at the time of Jesus’ greatest need (14:37). Judas betrays Him, Peter denies Him and when Jesus is arrested, they all desert Him (14:50). This is direct disobedience to the call to follow Him in suffering in 8:34-37, making the disciples liable to the judgment announced in 8:38. It is also an explicit failure to keep their promise in 14:31. The flight of the naked young man in 14:52 "dramatizes the shamefulness of the disciple’s flight and satirizes the pretensions of Christians who claim to be ready for martyrdom." Tannehill notes:
This interpretation may be supported by the reference to the fine linen (sindon) worn by the young man. Elsewhere in the New Testament the word is only used of the cloth in which Jesus was buried (see 5:46 and par.). If this detail is significant, it suggests that this man was so sure of his loyalty that he comes dressed for death, but suddenly changes his mind when death is a real prospect. His nakedness emphasizes the shamefulness of his flight.
The disciples’ failure is contrasted with the behaviour of others who do what they will not; Simon who must "take up" Jesus’ cross (15:21), the centurion at the cross who makes the confession that Peter refused to make (15:39) and Joseph of Arimathea who cares for Jesus’ burial, a task one would expect His closest friends and family would care for (15:43-47).
Even after the resurrection, as noted earlier, the fear that characterized the disciples remains (16:8). If one accepts the shorter ending of Mark, the story is left open-ended. Will they meet with Jesus? If one accepts the longer ending, the question is hardly different. Will they overcome their fear and doubt, and believe?
While any positive qualities of story characters will attract, a reader will identify most easily and immediately with characters who seem to share the reader’s situation. Assuming that the majority of the first readers of the Gospel were Christians, they would relate most easily and immediately to characters in the story who respond positively to Jesus. The disciples, including the twelve, are the primary continuing characters who, at least at first, seem to respond in this way and so share this essential quality of the Christian reader’s self-understanding. I believe that the author of Mark anticipated this response by his readers. He composed his story so as to make use of this initial tendency to identify with the disciples in order to speak indirectly to the reader through the disciples’ story. In doing so, he first reinforces the positive view of the disciples which he anticipates from his readers, thus strengthening the tendency to identify with them. Then he reveals the inadequacy of the disciples’ response to Jesus, presents the disciples in conflict with Jesus on important issues, and finally shows the disciples as disastrous failures. The surprisingly negative development of the disciples’ story requires the reader to distance himself from them and their behavior. But something of the initial identification remains, for there are similarities between the problems of the disciples and problems which the first readers faced. This tension between identification and repulsion can lead the sensitive reader beyond a naively positive view of himself to self-criticism and repentance. The composition of Mark strongly suggests that the author, by the way in which he tells the disciples’ story, intended to awaken his readers to their failures as disciples and call them to repentance. Allowing at first the comfortable assumption that Jesus and his disciples (and with them the Christian reader) are basically in concord, the story reveals points of essential conflict. The reader is left with a choice, a choice represented by the differing ways of Jesus and the disciples. In the light of what Jesus demands, this choice is not easy.
The Christians in Rome at the time of Mark’s Gospel were experiencing persecution under the Emperor Titus. Some had abandoned their faith or even betrayed others. The Christians of Mark’s time could likely identify with the weakness, hesitation and unbelief of the disciples. Yet, they could also see these traits as a sign of the power of God’s grace of forgiveness and a means of hope to walk in the footsteps of Jesus even after failure. Borrell contends that Mark intended for Peter’s denial to cause his readers to question their own conduct and attitudes so that they might respond more appropriately to Jesus’ death than Peter and the other disciples did. Jesus’ prediction of Peter’s denial suggests, in Borrell’s view, that failure is not the last word to be associated with the disciples, that the disciples are not ultimately discredited. Borrell points out that when Jesus speaks of his return to Galilee, preceding his disciples (14:28), this is to be understood as a patent link to 16:7 and is a clear invitation to reunification. For those who, like Mark (cf. Acts 15:38) and Peter, failed in the face of opposition, this would have provided tremendous encouragement and hope.
In chapter 13, Jesus assumes a restored relationship with those He recognizes will fail Him. Looking ahead to the future, He warns them to "watch" (13:33-37), even though He knows that they will fail to watch in Gethsemane (14:37). He warns them that they will be handed over to "councils" (13:9) just as He will be. He warns them that they will appear before governors and kings (13:9) just as He will. Even though they ran from this possibility at His passion, Mark anticipates that each reader will decide for himself how he will respond to the persecution facing him. Will he flee or obey? Will he doubt God or trust Him? The reader is left with a choice. How will his story end?
 Walter F. Sullivan, "The Gospel of Mark." The Catholic Virginian. January 17, 2003.
 Bruce Metzger, A Textual Commentary on the Greek New Testament: Second Edition. United Bible Societies, 1994: 102-106. Metzger: 102-103 notes:
The last twelve verses of the commonly received text of Mark are absent from the two oldest Greek manuscripts (a and B), from the Old Latin codex Bobiensis (itk), the Sinaitic Syriac manuscript, about one hundred Armenian manuscripts, and the two oldest Georgian manuscripts (written A.D. 897 and A.D. 913). Clement of Alexandria and Origen show no knowledge of the existence of these verses; furthermore Eusebius and Jerome attest that the passage was absent from almost all Greek copies of Mark known to them. The original form of the Eusebian sections (drawn up by Ammonius) makes no provision for numbering sections of the text after 16.8. Not a few manuscripts that contain the passage have scribal notes stating that older Greek copies lack it, and in other witnesses the passage is marked with asterisks or obeli, the conventional signs used by copyists to indicate a spurious addition to a document.
After examining the textual evidence for the fours possible endings of Mark, he concludes: 104, "On the basis of good external evidence and strong internal considerations it appears that the earliest ascertainable form of the Gospel of Mark ended with 16.8."
 Robert C. Tannehill, "The Disciples in Mark: The Function of a Narrative Role." Journal of Religion 57, 1977: 404
 This may be why Jesus instructed them not to tell anyone about Him after Peter’s confession in 8:29. Their lack of understanding would have made them inadequate messengers. "It is not as if the disciples had discerned the nature of Jesus but are prohibited from broadcasting it, but it is that the disciples have a wrong conception about his nature." - Joseph B. Tyson, The Blindness of the Disciples in Mark. Reprinted in The Messianic Secret, ed. Christopher Tuckett, Fortress, 1983: 36
 Tannehill: 400
 Ibid: 402
 Ibid: 403
 Ibid: footnote 38
 This verb is the same as in Jesus’ call to take up the cross and follow Him in 8:34.
 Ibid: 404-405
 Ibid: 392-393.
 Agustí Borrell, The Good News of Peter's Denial: A Narrative and Rhetorical Reading of Mark 14:54.66-72. trans. Sean Conlon. University of South Florida International Studies in Formative Christianity and Judaism 7. Scholars Press, 1998: 80-82.
 It is significant, of course, to note that following the reception of the Holy Spirit in Acts 2, the disciples became changed men. Whereas previously they had been characterized by fear, now they became bold witnesses of the resurrection of Jesus Christ. This is not to say that they did not still struggle with fear from time to time. Mark's desertion in Pamphylia (Acts 13:13) and Peter's withdrawal from the Gentiles because of fear (Galatians 2:11-14) stand as marked reminders of the disciple's continued need to choose obedience over disobedience, to live by faith rather than to allow fear to control one's life.