In the gospel Jesus knows well who he chooses and why he chooses him, on this occasion, he calls men who cast the net into the sea without knowing what types of fish they will catch. In the same way, when a catholic addresses his word to people, he does not know in advance who will approach God.
Jesus chose humble, poor, simple people, without great academic training, without influences, etc. This helps us not to be afraid and not think that we must be gifted in knowledge to follow Jesus. Peter and Andrew had not seen Jesus perform miracles, however, upon hearing Jesus' voice, they left everything to follow him. Surely, they saw the sweetness of the soul of the one who invited them.
They believed and had faith. It teaches us that we should not cling to earthly things if we want to go to eternal life. Each of us is beloved of the Lord, let us discover that calling in ourselves, let us be silent in our hearts to listen to the voice of God, and let us follow in the footsteps of Jesus.