Passage
Therefore Jehovah will set up on high against him the adversaries of Rezin, and will stir up his enemies,
Therefore Jehovah will set up on high against him the adversaries of Rezin, and will stir up his enemies,
Isaiah 9:9 And all the people shall know, [even] Ephraim and the inhabitant of Samaria, that say in pride and in stoutness of heart,
Isaiah 9:10 The bricks are fallen, but we will build with hewn stone; the sycomores are cut down, but we will put cedars in their place.
Isaiah 9:11 Therefore Jehovah will set up on high against him the adversaries of Rezin, and will stir up his enemies,
Isaiah 9:12 the Syrians before, and the Philistines behind; and they shall devour Israel with open mouth. For all this his anger is not turned away, but his hand is stretched out still.
Isaiah 9:13 Yet the people have not turned unto him that smote them, neither have they sought Jehovah of hosts.
The verse centers on "therefore", "jehovah", "high", "against", "adversaries", "rezin", "stir", and "enemies". It is saying that the verse draws attention to "therefore" and "jehovah", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 10's "The bricks are fallen but we will..." into verse 12's "the Syrians before and the Philistines behind...", so "therefore" and "jehovah" belong inside that flow. In Isaiah context, the local focus is the Holy One of Israel, judgment and restoration, the servant of the LORD, and Zion's hope.
A plain takeaway is to answer the verse's own emphasis on "therefore" and "jehovah" with trust shaped by these words, not by a vague optimism outside the passage.