Rashi on Isaiah
the Name of the Lord His might, which will be for Him as a name, viz., what He will do to Sennacherib.
Ibn Ezra on Isaiah
The name of the Lord, the report of what He has done to the army of Assyria.
Rashi on Isaiah
comes from long ago (מִמֶּרְחָק, lit. from afar.) To realize what He promised long ago.