Charles Spurgeon Commentary Mark 1:29

"And straightway, when they were come out of the synagogue, they came into the house of Simon and Andrew, with James and John." — Mark 1:29 (ASV)

And forthwith, when they were come out of the synagogue, they entered into the house of Simon and Andrew, with James and John.

"Forthwith," or, again, "immediately." Simon and Andrew and James and John were intimately connected; we are told that they were "partners" in their fishing business. James and John, the sons of Zebedee, seem to have been in a good position in life; we read that their father had "hired servants" employed in the boats. So James and John went with Simon and Andrew into their partners' house when Christ went there after performing that notable miracle in the synagogue.