Mark has already told his readers that Jesus is the Son of God, and he’s done a pretty good job of backing that up in what he showed in Chapter 1. John the Baptist pointed the way to him. God himself said Jesus was his son. Even the demons knew who he was and called him the Holy One of God. Then there’s the healing, the authoritative teaching, and the power over the demons.
Not everyone that Jesus encounters accepts who he is, though.
In Mark Chapter 2 and the first part of Chapter 3, there are five stories, all of which show growing opposition. In the course of that opposition, Mark poses another question that we need to consider.