Before a national disaster strikes, God extends a profound measure of personal grace to King Josiah. The king receives a divine promise assuring him that he will be gathered and brought to his resting place with dignity and honor [מצודת ציון, ביאור שטיינזלץ]. This protective gathering guarantees that he will neither end his days in exile nor be buried in a foreign land [מצודת דוד].
God assures the king that his passing will occur in peace. This guarantee presents a historical difficulty, as Josiah ultimately loses his life in the midst of battle. The promised peace, however, does not describe the physical circumstances of his death. Instead, it signifies that he will be spared from living through the catastrophic ruin destined for Israel [רש״י, מצודת דוד]. Specifically, God grants him the mercy of passing away before he has to witness the destruction of the Temple with his own eyes [רש״י].
Following this revelation, the king's messengers, Hilkiah and his companions, make their way back to the royal court to deliver the prophetic message directly to Josiah [מצודת דוד, ביאור שטיינזלץ].