There is a big difference between being called by God and just doing a job or choosing a career path. All Christians are called to be disciples and with that comes certain benefits and responsibilities.
In Luke 5:3 we see that Peter had been fishing all night and caught nothing. However, when Peter followed Jesus’ instruction and cast the net in again, it became full to breaking point.
Peter was a fisherman, he knew about fishing; Jesus was a carpenter, and his instruction wasn’t logical. But Jesus is the son of God, and that makes all the difference.
On that eventful day, Peter’s life changed forever. He would no longer be just a fisherman, but a fisher of men. He left everything and followed Jesus. Peter didn’t just have a new job, but a 24/7 calling. His life took a completely different direction and eventually he would give his life because of his calling.
Being called, and knowing he was called made all the difference to Peter and enabled him to stick to his course through thick and thin.