At once 

“As Jesus 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.” (MT 4: 18-20) 

Such a simple situation: “Jesus was walking by the Sea of Galilee” and saw two brothers “casting a net into the sea” and invited them: “Come after me, and I will make you fishers of men.” This life-changing decision was so simple for them: “At once they left their nets and followed him.” We are called by Jesus when we do our daily things, when we are with our “nets” on our “seas;” we also can improve our “at once.” 

“Come after me, says the Lord, and I will make you fishers of men.” (Gospel acclamation)