This is the end of the part of the story about the beginning of Jesus's ministry in Galilee. The rest of this chapter summarizes what he did and how the people responded. (See: [[rc://en/ta/man/jit/writing-endofstory]])
Here "kingdom" refers to God's reign as king. Alternate translation: "preaching the good news that God will show himself as king" (See: [[rc://en/ta/man/jit/figs-metonymy]])
The words "disease" and "sickness" are closely related but should be translated as two different words if possible. "Disease" is what causes a person to be sick. "Sickness" is the physical weakness or affliction that results from having a disease.