Because the appointed time has come, and the kingdom of God has come near, people should repent and believe in the gospel. Christ — the King — is both the message and the messenger. His first disciples exhibit the appropriate response to Christ’s radical claim: radical obedience
Like Simon and Andrew, Jesus calls James and John — an authoritative summons from the King. They respond appropriately: immediate, radical discipleship. They leave their family and their family business and begin to follow Jesus — to Whom everything else must be secondary.
Following the call of Simon and Andrew, Jesus fishes for their fishing partners: James and John. These “sons of thunder” — along with Simon (Peter) will form Jesus’ inner circle.
After being summoned by Jesus to become fishers of people, Simon and Andrew immediately drop their fishing nets and follow Jesus. They demonstrate the appropriate reponse to Christ’s authoritative call to discipleship — a call to complete and utter devotion to Him over everything and everyone else.
Simon and Andrew were fishers of fish; Jesus calls them to be fishers of people. That is, to catch people (once again, they were using nets not rods) and bring them into the inbreaking kingdom of God as they preach the Good News of Christ the King.
After Jesus’ proclamation concerning repentance and faith in the Gospel in response to the inbreaking kingdom of God (Mk 1:14-15), Jesus fishes for His first followers on the Sea (lake) of Galilee. Mark records Simon and Andrew as the first to respond appropriately to the summons of King Jesus