The Twelve had cast out demons during the course of their Third Galilean Tour (see ch. 6:13). They were at a loss to account for the fact that the power that Jesus had imparted should have departed from them.
The house.
The definite article, “the,” implies that this was a particular house that Christ considered His home, possibly Peter’s home in Capernaum (see on chs. 1:29; 2:1), a temporary home for Jesus during the remainder of His stay in Galilee (cf. DA 432).