Upon discovering that Hezekiah is actively preparing to rebel against him, Sennacherib decides to respond. He sends Rabshakeh along with other messengers to Jerusalem [מלבי ם]. At this time, the King of Assyria is fully occupied waging war and laying siege to the city of Lachish, accompanied by his entire army [מצודת דוד, ביאור שטיינזלץ]. Because he is tied down in battle, he relies on this delegation to confront the leadership in Jerusalem.
The messengers are sent directly to King Hezekiah [מצודת דוד]. However, their mission goes beyond merely speaking to the royal leadership. The delegation is instructed to simultaneously address all the people of Judah who are besieged in the city. This creates a twofold strategy. While officially delivering a message to the king, the messengers aim to speak directly to the trapped population in order to crush their morale, break their confidence, and demand their surrender [ביאור שטיינזלץ].