Completing the Temple provided a unique opportunity to publicly and fully celebrate its dedication alongside the Festival of Unleavened Bread. Although the altar was already standing, and the Passover sacrifice might have been offered earlier, it was the final completion of the building that brought about a sense of total joy [ביאור שטיינזלץ].
This great joy was deeply rooted in the recognition of Divine intervention. God actively turned the heart of the king to look upon the Jewish people with favor [מצודת ציון, מצודת דוד, ביאור שטיינזלץ]. This newfound royal support strengthened the people in highly practical ways. The king funded the construction costs, shielded the builders from enemies who sought to halt their progress [מצודת דוד], and extended his assistance to the Jews still living in exile within the Assyrian territories [רש"י].
A fascinating historical detail emerges regarding the ruler's title. At this time, the Persian Empire held power, yet the ruler is referred to as the king of Assyria. Commentators offer several explanations for this shift. Some identify the king as Darius, noting that he ruled over the ancient territories of Assyria, which had once been the region's dominant superpower [מצודת דוד]. Others identify him as Artaxerxes [אבן עזרא]. It is also possible that the Persian king viewed himself as the direct successor to the great monarchs of Assyria and Babylon [ביאור שטיינזלץ]. Another perspective suggests that the title represents the royal ministers as a whole; officials who had previously oppressed the Jewish people were now actively supporting them [מלבי"ם].
Beyond the historical identity of the king, the specific mention of Assyria highlights a profound spiritual and historical reversal. In the past, it was the kings of Assyria who had brought destruction upon the land of Israel. Now, God had completely transformed the heart of the ruling empire, shifting its intentions from harm to good. The very superpower historically responsible for destruction was now the primary force assisting in the rebuilding of God's House [אבן עזרא].