The passage
      v14-15. Mark separates the ministry of Jesus from that of John. Only after the arrest of John does Jesus begin his ministry in earnest. So, John prepares the way for Jesus' coming, 1:2. Mark differentiates Jesus' message from John's, although Matthew implies that they are the same, 3:2. John calls for repentance in the face of the coming-one who brings with him the cleansing Spirit. This call finds fulfillment in Jesus.
      Jesus communicates the "gospel" or "good news." The word actually means "important message". It is either good news, or bad news, depending on how we respond to it. There are three parts to the message and Mark gives us a summary:
        i] "The time has come", or "the time is fulfilled/completed". All that the prophets foretold concerning the coming of the messiah, the anointed Davidic leader, is coming to fruition in and through the person of Jesus.
        ii] "The Kingdom of God is near", "at hand / bursting in upon us." The glorious day when God will gather a people to himself to eternally live secure under his rule of peace, is bursting into this world. Again, this is actualized in the person of Jesus, who both inaugurates it in the present moment, and will realize it at his second coming.
        iii] "Repent and believe". The message demands a response. The call for repentance is similar to John's call. Membership in the coming kingdom demands a turning toward the living God. It is a turning back to God, a conversion. The response also involves belief: faith, dependence on, firm reliance on, a reliance on the gospel for salvation. Both John and Jesus link "repent and believe" with "forgiveness". Our response to the gospel involves both a turning to God and a reliance on God, for mercy, for God's free grace of forgiveness in Christ.
      v16-18. The two fishermen, Simon and Andrew, are called first. John tells us that they were disciples of John the Baptist and were therefore well prepared for the call, Jn.1:35-42. They are called to be "fishers of men." The term has Old Testament significance. In the day of judgement, God will cast his net out over the sea of humanity and gather some for life and others for damnation. The disciples are called to gather in the lost before the dawning of that terrible day. As already noted, the gospel of the coming kingdom is both good and bad news.
      v19-20. James and John are called next. The context implies that they too will serve as messengers of coming judgement, gathering and separating. They, like Simon and Andrew, immediately accept the sovereign call of God in Jesus. Given the one who calls, they have no other choice. Their return to Galilee, at the end of Mark's gospel, serves to reaffirm and refocus this call to mission, 16:7, cf. John chapter 21.

An effectual call
      One of the subjects of constant debate in a theological college is the function of the gospel in salvation. All agree it is "the power of God unto salvation", but how does this power work? Students tend to break up into two groups. Some feel that it is a power available for the seeker, that is, for the person who is seeking God it serves as the key to unlock the grace of salvation. Such a view emphasizes the notion of human freewill in the process of salvation. Others feel that it is a preemptive power which acts on a person who has already experienced a sovereign inworking of the Spirit. Such a view emphasizes the notion of God's sovereign will in the process of salvation.
      Biblical truth is truth in tension. So, in this instance, the Bible does seem to affirm both God's sovereignty and human freedom. The call of the disciples illustrates both sides of the divide; the theological truth known as the "effectual call" and on the other side of the divide, human freewill. On the one hand, we could argue that the disciples had no choice in the matter. The call of Jesus left them with no option other than leave all and follow him. Their service to Jesus would involve communicating that same call to others. They too would become "fishers of men." Yet, their call was not out of the blue. They were already followers of John the Baptist and were looking for the coming messiah. They had thought through the issues and were ready and waiting when the net was cast.
      Today we possess a gospel with the same power, and have the same authority to cast its net far and wide. The gospel actually makes our job simple. We must widely and clearly communicate its message. Its effective power is the responsibility of God, while its personal touch is the responsibility of the seeker. What mustn't be lost on us is the urgency of its communication, for the day of judgement is at hand. Thus, we point to the hope of eternal life in Christ and call on everyone everywhere to turn and put their trust in Jesus.

v15
      Mark now outlines the actual message communicated by Jesus. Matthew has John communicating the same message, 3:2, although John's message is qualified by the fact that the inauguration of the kingdom is in the hands of the coming messiah. John's task is to prepare Israel for messiah's coming. Mark emphasizes John's preparatory role and leaves Jesus to communicate the message.
      oJti Here denoting direct speech.
      oJ kairoV (oV) "the time" - opportune time, appointed time. "A specific quality of a particular period of time", Cullmann.
      peplhrwtai (plhrow) perf. "has come" - has been fulfilled, filled up to overflowing. The sense "completed" is best, in that the prophecies concerning the coming of the messiah and the inauguration of his kingdom, have now come to fruition in the person and work of Christ, therefore, the kingdom is upon us, is "now". The perfect tense underlines the idea of completion. "The time, prophesied long ago, has come at last."
      hJ basileia (a) "the kingdom" - The reign of God. Referring to the eternal reign / rule / kingship of God now open to all people in and through the ministry the messiah. The gathering of this people and the exercise of this reign, is inaugurated and comes to fruition, in the person and work of Jesus. Its reality is imaged in the Old Testament, particularly in the historic kingdom of Israel, before finding its fulfilment in Jesus. There is, of course, debate over whether the kingdom is a time/space reality, or just a symbol. The concept, namely "the reign of God", has more going for it than a symbol, "the idea of God's sovereignty", although we are more likely dealing with "the reality of God's reign in Christ."
      tou qeou "of God" - A possessive sense seems best.
      hggiken (eggizw) perf. "is near" - has come near, approached, drawn near. Drawing near expresses motion toward, so the perfect tense is probably expressing the idea that the motion in time toward the realization of the kingdom has virtually reached its completion, therefore "at hand", "near", although better, "upon", "rubbing up next to." Of course, the word leads to the great debate over the "now and/or, not yet" shape of the kingdom. Without in any way denying that the kingdom of God is yet to be fully realized in the return of Christ, there is still much to be said for Dodd's version or realized eschatology, although we are on safer ground with an inaugurated eschatology. "The kingdom of God is bursting in upon you."
      metanoiete (metanoew) imp. "repent" - change [your direction]. The word carries the sense, "turn around", so the imperative is "turn from your opposition to / abandonment of, God", "turn to God", "be converted." Of course, the word "repent" means something quite different in modern language, so we are best not to use it; "turn back to God", CEV.
      pisteuete en "believe" - believe in [the important message]. The sense of "believe in" may be "believe in (the sphere of) the gospel", Moule IB. Most commentators hold it just means "believe the message." The sense of the word "believe", is "to put one's weight on", "rest firmly on", rather than "give intellectual ascent to."

v16
      paragwn (paragw) pres. part. "As [Jesus] walked beside" - passing by. The variant "walking" is, in any case, the sense of "passing along/by." Probably a temporal participle, "when (while) Jesus was walking along the shore", Barclay.
      thn qalassan (a) "sea" - It was properly a lake, although Mark calls it a sea. Jesus focuses his ministry on the Jewish towns around the lake, making his headquarters Capernaum.
      alieiV (uV ewV) "fisherman" - It is fascinating to note that common fishermen are called to serve as Jesus' apostles (the sent ones), although note that Zebedee employed "hired men", indicating that James and John were not at the bottom of the social scale, v20.

v17
      deute "come" - come here. Plural form of the adverb serving as an imperatival interjection.
      opisw mou "follow me" - after me. An invitation to take up an apprenticeship with the rabbi Jesus, although in rather stark terms; "Here! Behind me", France. It is most likely that these disciples of John knew Jesus well and now that John had been arrested, were given the opportunity to serve the one John had pointed to.
      poihsw (poiew) fut. "I will make" - Used in the sense of "cause someone to do something", Cranfield, so "I will make you become in the future, after a course of preparation, ...", Grant.
      alieiV anqrwpwn "fishers of men" - fisherman of men. "Fishermen who fish for men." In Jeremiah 16:16, we read of God sending his servants to fish-out his people for judgment, for blessing or cursing, cf. Am.4:2, Hab.1:14-17, also Ezk.47:8-10. This image may well prompt Jesus use of a fishing metaphor here and so remind us again that the preaching of the gospel is like a two edge sword, it both blesses and curses. If the Old Testament allusion is somewhat strained, we are bound to read back a knowledge of the Christian mission to make sense of the metaphor. The disciples will gather people into the kingdom through the preaching of the gospel; "I will make you fishermen who catch men", Barclay.

v18
      afenteV (afihmi) aor. part. "they left" - leaving, abandoning. The act of leaving their nets may serve to illustrate a renunciation of the world in service to Jesus, but since we know that the disciples retained their property, including fishing boats, Jn.21:3, it is more likely that they packed up their gear for the time being in order to go on mission with their new rabbi.
      ta diktua auton "their nets" - the nets of theirs. The word can mean any net, although probably "casting net" is intended.
      hkolouqhsan (akolouqew) aor. "followed [him]" - they followed after. A literal "following" is probably intended, "went with him", CEV, although a derived sense may be present, ie. "follow as a disciple", "became his followers", Barclay.

v19
      en tw/ ploiw/ "in a boat" - in, with, by the boat. The definite article need not be translated, in fact may mean "their", while the preposition is unlikely to mean "in" as the last place a person works on a net is in the confined space of a boat.
      katarizontaV (katartizw) part. "preparing" - mending, restoring, strengthening. As noted by Cranfield, obviously "preparing" their nets for the next day's fishing: mending, cleaning, folding, etc. The participle possibly forms a temporal clause, "while they were preparing their nets", or a relative clause "who were in the boat mending their nets", RSV.