Matthew, just like the other evangelists, is not writing a biography of the Messiah, but reports only the facts relevant to his theme, which is to show that Jesus was the King of Israel and the Messiah promised in the prophecies of the Old Testament, giving his personal testimony about His person.
This explains a gap of about a year between verses 11 and 12 of this chapter, during which the Lord Jesus, on returning from desert after his temptation, passed again by John the Baptist, was introduced to Andrew, Simon (who he nicknamed Peter), Philip, Nathaniel, and did his first miracle at Cana of Galilee.
With these disciples, his mother and his brothers and sisters, he went down to Capernaum in Galilee, then went again to Jerusalem shortly before Passover, purified the temple from the presence of traders, did miraculous signs and interviewed the Pharisee Nicodemus, a religious authority, to whom He explained the Gospel (John 3:14-18). Then He went with his disciples to Judea, and many people came to Him, even more than went to John, and His disciples baptized them.
He returned later to Galilee through Samaria, where he had a famous dialogue with a Samaritan woman, resulting in many Samaritans believing in Him. He passed by Cana again, from where he cured the son of an officer of the King who was far away in Capernaum.
These facts are all reported in the Gospel of John, chapters 1:29 to 4:54.
At this point Matthew continues his Gospel, explaining that Jesus returned to Galilee after hearing that John the Baptist had been arrested.
The Lord Jesus transferred his residence to Capernaum, on the shore of the Sea of Galilee, after being rejected by the Jews in the synagogue of Nazareth. These sought to kill him when he mentioned the cases of two Gentiles, the widow of Sarepta and Naaman the Syrian, whom God answered rather than the people of Israel (Luke 4:16-30).
This fulfilled a prophecy from the Old Testament (Isaiah 9:1,2), that the inhabitants by the way of the sea, Galilee of the Gentiles, in the land of tribes of Zebulon and Naphtali, who walked in darkness would see a great light, representing the Messiah who would bring them eternal life.
In fact, the Lord Jesus began preaching repentance there, because the kingdom of heaven was near. It was the message preached by John the Baptist as the herald, but the Lord Jesus was the King himself, and wished that people would go through a moral transformation in order to qualify to be His subjects.
On the shore of the sea of Galilee, the Lord Jesus again found Simon, who He had called Peter, and Andrew. The two were working in their occupation of fishermen.
Luke tells us in his Gospel that the Lord Jesus had healed the mother-in-law of Simon of a serious illness, and that on this occasion Simon and Andrew went to fish without any success until the Lord Jesus showed them where to throw their nets. They caught so many fish that they had to ask for assistance because the boat was sinking under the weight.
Simon was very impressed, and asked the Lord to stay away because he (Simon) was a sinful man (Luke 5:1-7).
This time He invited them to follow Him, to learn to be "fishers of men". For that, they had to know Christ personally, following in His footsteps and receiving His teaching. They would have to follow His example. He would be their Master, or Rabbi, the name by which they called him.
They would have to know His character, to imitate Him later in this new task. Their character should become godly, which was more important than eloquence, knowledge of philosophy or skill in argumentation.
As well as every fisherman, the fisher of men needs to learn where to find the “fish”, to use the proper bait, to suffer discomfort and inconvenience with patience, and to stay out of sight.
Simon and Andrew promptly attended the call and left all they were doing. They already knew that Jesus was the Messiah of God.
Then, He called two other brothers, also fishermen: James and John. They had helped in that fishing, and undoubtedly knew who Jesus was, so they did not hesitate in leaving the boat in the hands of their father, Zebedee and their employees and followed the Lord Jesus, who got all their priority.
These disciples, boldly willing to leave everything to follow their Master, were appointed apostles later and were of fundamental importance for the preaching of the Gospel, beginning in Jerusalem and then throughout the world.
Even today, nearly two millennia later, they are well known and we are still learning from the two letters of Peter, and the Gospel and three letters of John. If these fishermen had rejected the invitation of the Lord Jesus and continued in their humble professions, they would have been forgotten soon after their death.
The ministry of the Lord Jesus involved three aspects:
Teaching in the synagogues: synagogues were educational institutions, there being no separation between the "secular" and the "religious". The teachers were the Levites, "doctors of the law", whose main function was teaching. However, they allowed the Lord Jesus to speak in there, no doubt because of His deep knowledge of the Scriptures and the authority with which He taught.
The preaching of the good news (Gospel) of the Kingdom: the Lord Jesus did not limit himself to teaching in their synagogues, but He also taught his disciples and the crowds who came to hear him. We have examples of his teaching in chapters 5 to 7.
The healing of illnesses and diseases of the people: one of the purposes of the miracles of healing, called "signs", was to demonstrate to everyone His divine identity, thus authenticating His ministry (Hebrews 2: 3,4). This was the first of three "missionary journeys" made by the Lord Jesus throughout the Roman province of Galilee. This time He was accompanied by the four fishermen who he had called.
The second time He took the twelve apostles. On the third He sent the twelve in front, two by two, and followed them later. He taught the Gospel of the Kingdom in the synagogues, but also in the streets and roads where the Gentiles could hear.
In verse 23 the word "gospel" first appears in the Bible. It simply means "good news of salvation", and is summarized in the words of the Lord Jesus to Nicodemus: "For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.” (John 3:16).
At that time there was no radio, let alone television, but the stunning news about the Messiah, his teaching and the cures He operated, spread rapidly by word of mouth, and it is no wonder that people came from everywhere to Galilee to meet Him. Even Gentiles came from Syria.
The result did not take long: it was like a moving hospital with thousands of patients asking for healing, in addition to the curious and those who actually wished to prove the reality of His person. Chronic and incurable diseases of all kinds were to be found in the crowd, as well as demon-possessed, lunatics, paraplegics, epileptics (these diseases are called "torments"). There were crowds and crowds.
12 Now when Jesus heard that John had been put in prison, He departed to Galilee.
13 And leaving Nazareth, He came and dwelt in Capernaum, which is by the sea, in the regions of Zebulun and Naphtali,
14 that it might be fulfilled which was spoken by Isaiah the prophet, saying:
15 "THE LAND OF ZEBULUN AND THE LAND OF NAPHTALI, BY THE WAY OF THE SEA, BEYOND THE JORDAN, GALILEE OF THE GENTILES:
16 THE PEOPLE WHO SAT IN DARKNESS HAVE SEEN A GREAT LIGHT, AND UPON THOSE WHO SAT IN THE REGION AND SHADOW OF DEATH LIGHT HAS DAWNED."
17 From that time Jesus began to preach and to say, "Repent, for the kingdom of heaven is at hand."
18 And Jesus, walking by the Sea of Galilee, saw two brothers, Simon called Peter, and Andrew his brother, casting a net into the sea; for they were fishermen.
19 Then He said to them, "Follow Me, and I will make you fishers of men."
20 They immediately left their nets and followed Him.
21 Going on from there, He saw two other brothers, James the son of Zebedee, and John his brother, in the boat with Zebedee their father, mending their nets. He called them,
22 and immediately they left the boat and their father, and followed Him.
23 And Jesus went about all Galilee, teaching in their synagogues, preaching the gospel of the kingdom, and healing all kinds of sickness and all kinds of disease among the people.
24 Then His fame went throughout all Syria; and they brought to Him all sick people who were afflicted with various diseases and torments, and those who were demon-possessed, epileptics, and paralytics; and He healed them.
Mat 4:25 Great multitudes followed Him—from Galilee, and from Decapolis, Jerusalem, Judea, and beyond the Jordan.
Matthew chapter 4, verses 12 to 25