29. And forthwith, when they were come out of the synagogue--so also in Lu 4:38.
      they entered into the house of Simon and Andrew, with James and John--The mention of these four--which is peculiar to Mark--is the first of those traces of Peter's hand in this Gospel, of which we shall find many more. The house being his, and the illness and cure so nearly affecting himself, it is interesting to observe this minute specification of the number and names of the witnesses; interesting also as the first occasion on which the sacred triumvirate of Peter and James and John are selected from among the rest, to be a threefold cord of testimony to certain events in their Lord's life (see on Mr 5:37) --Andrew being present on this occasion, as the occurrence took place in his own house.

JFB.