Jesus went all over Galilee teaching in the [Jewish] synagogues and preaching the good news of the [coming, see verse 17] kingdom, and healing all kinds of disease and sickness among the people.
So, Jesus went into the [Jewish] synagogues throughout all Galilee, preaching [the good news about the coming kingdom, verses 14- 15] and driving out evil spirits.
Now it happened while Jesus was standing on the shore of Lake Genneseret [i.e., Lake Galilee] that the crowd was pushing closer to Him to hear God’s message.