How was it different for Andrew and Simon (Peter) to be disciples of Jesus now compared to being disciples of John the Baptist at first?
We see that Simon (Peter) and Andrew first follow Jesus (John 1:37–51). However, now they must follow him day and night. They can no longer continue to do their ordinary work, as in the time when they were John’s disciples. That was the custom in those days: people from Israel chose a certain teacher (rabbi) but kept their daily work for their livelihood.
18 Comme il marchait le long de la mer de Galilée, il vit deux frères, Simon, appelé Pierre, et André, son frère, qui jetaient un filet dans la mer; car ils étaient pêcheurs.