A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
ezr 6:1DARIUS' DECREE FOR ADVANCING THE BUILDING. (Ezr 6:1-12)
Darius the king--This was Darius Hystaspes. Great and interesting light has been thrown on the history of this monarch and the transaction of his reign, by the decipherment of the cuneatic inscriptions on the rocks at Behistun.
in the house of the rolls, where the treasures were laid up in Babylon--An idea of the form of this Babylonian register house, as well as the manner of preserving public records within its repositories, can be obtained from the discoveries at Nineveh. Two small chambers were discovered in the palace of Koyunjik, which, from the fragments found in them, MR. LAYARD considers "as a house of the rolls." After reminding his readers that the historical records and public documents of the Assyrians were kept on tablets and cylinders of baked clay, many specimens of which have been found, he goes on to say, "The chambers I am describing appear to have been a depository in the palace of Nineveh for such documents. To the height of a foot or more from the floor they were entirely filled with them; some entire, but the greater part broken into many fragments, probably by the falling in of the upper part of the building. They were of different sizes; the largest tablets were flat, and measured about nine inches by six and a half inches; the smaller were slightly convex, and some were not more than an inch long, with but one or two lines of writing. The cuneiform characters on most of them were singularly sharp and well-defined, but so minute in some instances as to be almost illegible without a magnifying glass. These documents appear to be of various kinds. The documents that have thus been discovered in the house of rolls' at Nineveh probably exceed all that have yet been afforded by the monuments of Egypt, and when the innumerable fragments are put together and transcribed, the publication of these records will be of the greatest importance to the history of the ancient world" [Nineveh and Babylon].
ezr 6:2Achmetha--long supposed to be the capital of Greater Media (the Ecbatana of classical, the Hamadan of modern times), [is] at the foot of the Elwund range of hills, where, for its coolness and salubrity, Cyrus and his successors on the Persian throne established their summer residence. There was another city, however, of this name, the Ecbatana of Atropatene, and the most ancient capital of northern Media, and recently identified by COLONEL RAWLINSON in the remarkable ruins of Takht-i-Soleiman. Yet as everything tends to show the attachment of Cyrus to his native city, the Atropatenian Ecbatana, rather than to the stronger capital of Greater Media, COLONEL RAWLINSON is inclined to think that he deposited there, in his fortress, the famous decree relating to the Jews, along with the other records and treasures of his empire [Nineveh and Persepolis].
ezr 6:8of the king's goods, even of the tribute beyond the river . . . expenses be given unto these men--The decree granted them the privilege of drawing from his provincial treasury of Syria, to the amount of whatever they required for the furthering of the work and providing sacrifice for the service of the temple, that the priests might daily pray for the health of the king and the prosperity of the empire.
ezr 6:11whosoever shall alter this word--The warning was specially directed against the turbulent and fanatical Samaritans. The extremely favorable purport of this edict was no doubt owing in some measure to the influence of Cyrus, of whom Darius entertained a high admiration, and whose two daughters he had married. But it proceeded still more from the deep impressions made even on the idolatrous people of that country and that age, as to the being and providence of the God of Israel.
ezr 6:13THE TEMPLE FINISHED. (Ezr 6:13-15)
Then Tatnai . . . did speedily--A concurrence of favorable events is mentioned as accelerating the restoration of the temple and infusing a new spirit and energy into the workmen, who now labored with unabating assiduity till it was brought to a completion. Its foundation was laid in April, 536 B.C. (Ezr 3:8-10), and it was completed on February 21, 515 B.C., being twenty-one years after it was begun [LIGHTFOOT].
ezr 6:16FEASTS OF THE DEDICATION. (Ezr 6:16-18)
the children of Israel . . . kept the dedication . . . with joy--The ceremonial was gone through with demonstrations of the liveliest joy. The aged who had wept at the laying of the foundation [Ezr 3:12] were most, if not all of them, now dead; and all rejoiced at the completion of this national undertaking.
ezr 6:17twelve he-goats--as at the dedication of the tabernacle (Num 7:87; Num 8:17).
ezr 6:18they set the priests in their divisions, and the Levites in their courses . . . as it is written in the book of Moses--Although David arranged the priests and Levites in courses according to their families, it was Moses who assigned to the priests and Levites their rights and privileges, their stations and several duties.
ezr 6:21AND OF THE PASSOVER. (Ezr 6:19-22)
all such as had separated themselves . . . from the filthiness of the heathen of the land--that is, who had given satisfactory evidence of being true proselytes by not only renouncing the impure worship of idolatry, but by undergoing the rite of circumcision, a condition indispensable to a participation of the passover.
ezr 6:22kept 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.