A diverse coalition of nations united to draft a formal letter of accusation against the Jewish people returning to Zion. This alliance included various idol-worshipping groups who had been displaced from their homelands and resettled in the region.
The Assyrian king responsible for exiling and resettling these groups is the subject of historical debate. The primary approach among commentators identifies him as Sennacherib, recorded under his Persian name. Others suggest the monarch is actually Esarhaddon, who imported the nations that later converted out of a fear of lions, or perhaps that the name refers to Esarhaddon's father [רס״ג]. To resolve the apparent contradiction with earlier historical accounts which state that Esarhaddon settled these nations in Samaria, it is explained that the resettlement is attributed to Sennacherib because the son was merely carrying out his father's commands [מצודת דוד]. Another perspective simply views the name as a general title for the Assyrian king [ביאור שטיינזלץ]. Regardless of his exact identity, this great and respected ruler established these displaced nations in the towns and cities surrounding Samaria.
The letter of accusation was also supported by the rest of the peoples living on the western side of the Euphrates River. Because the Euphrates serves as a natural border between Babylon and the Land of Israel, the nations residing on the side of Israel are described as being "beyond the river" from the perspective of those living in Babylon.
The introduction to this letter concludes with a detail that carries a few different interpretations. One group of commentators understands it as a geographical reference, identifying a specific nation, city, or central district whose inhabitants also consented to the accusation [רש״י, מצודת דוד, רלב״ג, אבן עזרא]. Conversely, others interpret it as a structural transition meaning "and now." In this view, it serves to skip ahead and signal that the document is moving directly to its main point [אבן עזרא, רס״ג, ביאור שטיינזלץ]. A final interpretation suggests it relates to the concept of a response or appeasement, indicating that the letter began with soft, pleading language before delivering its formal reply [רס״ג].