This is a passage focused on the calling of Matthew, the writer of what to the modern reader is the first Gospel; but we also learn about the situation with Jesus. He is now preaching in the open air, as the doors of the synagogues have been shut in His face: the Jewish religious leaders have declared war and that is the first step along a road which leads to crucifixion. Just like John Wesley many centuries later, Jesus is forced to preach in the field and by the sea and so passers by and bystanders have an opportunity to hear Him. One such person may well have been Matthew. He was a tax collector, but unlike Zacchaeus - who collected for the Romans- he was a collector of Herod's taxes. Everyone hated tax collectors whoever they were collecting for. It was a job which they had to bid to get, the highest bidder won the post. The way to retrieve their investment was to charge more than they needed and so they were wealthy individuals, but did not have friends!
When Jesus called Matthew, he gave up everything to follow Him. We read in John's Gospel chapter 21 that, when Jesus died, the disciples who were fishermen went back to their fishing, that was easily done. There was no going back for Matthew, even if he had ever wanted to! However, he gained an ability to look at the world in the face again; he received a far bigger job than he had left behind-one which would consume him for the rest of his life and it brought him immortal and worldwide fame through the writing of his Gospel, a work of genius!
This story also tells us something about Jesus, who even when He was going for a stroll by the lake, was looking for opportunities. Some of my time with people is arranged and booked as you know, whereas there are times when I meet with someone in the street who I've wanted to speak to and it feels timely and less worrying for the other person! Jesus looked for men and women for His kingdom as He walked.