By choosing the synagogue as the place to preach, Jesus indicates right from the outset that he is seeking all the people and that he has to deliver a message to them in God’s name. This appearance in the synagogue is telling: Mark will tell us that Jesus will later preach in the countryside too, but that had an incidental cause and must be regarded as an extension of his preaching that he deliberately began in the synagogues.1
21 And they went into Capernaum, and immediately on the Sabbath he entered the synagogue and was teaching.