In these verses Isaiah has returned to the proud and arrogant northern ten tribes and the people of Syria. They think they are going to rebuild Jerusalem and replace the bricks with hewn stone. Where there have been sycamores they intend to have stately cedars. But all of this ambitious reconstruction will never come to pass. Nevertheless God will continue to have his arm stretched out still. To regain their blessings these people only need to return to the Lord, and adopt his ways.