matthew 4:25 And there followed him great multitudes of people from Galilee, and from Decapolis, and from Jerusalem, and from Judaea, and from beyond Jordan. - Free Bible Online

      25. And there followed him great multitudes of people from Galilee, and from Decapolis--a region lying to the east of the Jordan, so called as containing ten cities, founded and chiefly inhabited by Greek settlers.
      and from Jerusalem, and from beyond Jordan--meaning from Perea. Thus not only was all Palestine upheaved, but all the adjacent regions. But the more immediate object for which this is here mentioned is, to give the reader some idea both of the vast concourse and of the varied complexion of eager attendants upon the great Preacher, to whom the astonishing discourse of the next three chapters was addressed. On the importance which our Lord Himself attached to this first preaching circuit, and the preparation which He made for it, see on Mr 1:35-39.

JFB.