Notice how similar these three passages are:
Now as [Jesus] walked by the sea of Galilee, he saw Simon and Andrew his brother casting a net into the sea: for they were fishers. And Jesus said unto them, Come ye after me, and I will make you to become fishers of men. And straightway they forsook their nets, and followed him.
And when he had gone a little further thence, he saw James the son of Zebedee, and John his brother, who also were in the ship mending their nets. And straightway he called them: and they left their father Zebedee in the ship with the hired servants, and went after him.
And he went forth again by the sea side; and all the multitude resorted unto him, and he taught them. And as he passed by, he saw Levi the son of Alphæus sitting at the receipt of custom, and said unto him, Follow me. And he arose and followed him.
Now given that the first two passages are actually adjacent to each other (Mark 1:16-18 and 1:19-20), it might seem surprising that Mark didn’t simply compress them into one story. (My kids actually have writing exercises where they are supposed to combine similar material in order to write more efficiently: “Jan ate a burger. Jan ate fries.” is changed to “Jan ate a burger and fries.”) So why didn’t Mark combine these two calling stories? Maybe to emphasize their differences. First, it appears that Simon and Andrew are standing in the water, casting a net. But James and John have a boat and hired workers. So Mark might want to emphasize that, despite the fact that all four are fishermen, they are coming from different economic positions; the moral of the story would be that Jesus called disciples from a variety of stations in life. Second, James and John also leave their father. Maybe 2K years of Christianity makes that sound unremarkable to us, but I think that Mark’s audience might have heard a violation of the Fifth Commandment in that line. So presenting two separate call stories here–instead of compacting them into one–highlights the differences between the two.
The third story is even more interesting. It isn’t in Mark 1, where it would have been part of the “typical day in the life” of Jesus’ ministry that is presented there. It is in Mark 2, part of a group of five controversy stories (Mark 2:1-3:6), where opposition to Jesus is a feature in each story; this opposition begins in muted tones and increases in each event until, after the final story, Jesus’ death is plotted. Why put the calling of a disciple into the controversy stories? Because it was.
Levi is a tax collector. Hating on the IRS is such a cultural norm that it is easy to see Levi as the brunt of jokes and snide comments, but in his world, it was much, much worse than that. The Romans, clever devils, used a system of “tax farming;” instead of all of the muss and fuss of collecting taxes themselves, they auctioned the right to collect taxes in a certain area to the highest bidder, got their money up front, and left the dirty work to the lucky winner. That winner was allowed to collect pretty much whatever he could. For Levi to participate in this system (likely not as the big guy with the contract but as a lower-level employee of his) was to participate in a system thought to be inherently dishonest. But wait, there’s more! There are political implications here, because Roman rule in Galilee (which isn’t direct at this time, but I won’t bore you with the details) relies on these tax receipts, which means that, from a Jewish perspective, he is on the side of their hated conquerors and, in fact, makes their occupation possible. And, because he would have spent all of that time handling coins with pictures of the emperor and other pagan images on them and touching all of that unclean Gentile merchandise (because he’s collecting what we would call a customs tax on everything that comes down the road and/or off the boat), he was religiously suspect as well. In Jewish writings, these tax collectors are grouped with murderers and thieves. And it is possible that he had personally hassled Simon, Andrew, James, and John in the process of collecting taxes on the fish that they had caught.
And so here comes Jesus, calling this guy to follow him. Can you imagine the reaction of the other disciples? (Imagine your stereotypical upper-middle income suburban Jell-o belt ward and call a Hell’s Angel to their high council.) The calling of Levi isn’t a story about the calling of yet another interchangeable person to yet another church calling. It is the story of Jesus hand-selecting a group of people who are highly unlikely to get along, enjoy each other’s company, or even like each other very much. (And yet he expects them to be one, if you’ll excuse the dip into John’s Gospel.) The repetition across the three call stories emphasizes, I think, the deliberateness with which Jesus composed this group.
And Jesus expects these guys to live, work, travel, and learn together.