Jamieson, Fausset and Brown on Ezra 6:22

22. kept the feast ... with joy: for the Lord ... turned the heart of the king of Assyria unto them--that is, king of the Persian empire, which now included the possessions, and had surpassed the glory, of Assyria. The favorable disposition which Darius had evinced towards the Jews secured them peace and prosperity and the privileges of their own religion during the rest of his reign. The religious joy that so remarkably characterized the celebration of this feast, was testified by expressions of lively gratitude to God, whose overruling power and converting grace had produced so marvellous a change in the hearts of the mighty potentates, and disposed them, pagans though they were, to aid the cause and provide for the worship of the true God.