As he was walking by the Sea of Galilee, he saw two brothers, Simon who is called Peter, and his brother Andrew, casting a net into the sea; they were fishermen. He said to them, "Come after me, and I will make you fishers of men." At once they left their nets and followed him. He walked along from there and saw two other brothers, James, the son of Zebedee, and his brother John. They were in a boat, with their father Zebedee, mending their nets. He called them, and immediately they left their boat and their father and followed him. (Mt 4: 18-22)
In the present story Peter, Andrew, James, and John leave behind the nets and their father. Peter and Andrew were casting their nets in the sea for a catch. While they were in their job – as they were doing their job they leave and follow. (Not after much reflection and prayer and consultation and discernment.) They hear the call and they go at once. So also James and John; they were mending their nets (may be after a catch or getting ready for a catch) and when they were called they leave behind and follow.
In as much as following is important so also leaving something behind is important Many a times we like to keep something with us ( for security) and try to follow also the invitation. Following demands ( it seems so) a total leaving behind of things and persons. It is also following a person (JESUS) not an ideology or a principle or a dogma. Following a person seems to be easy. But leaving behind is not so. We like to walk forward (follow), but looking behind and not leaving behind.