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 8:1EZRA'S COMPANIONS FROM BABYLON. (Ezr 8:1-14)
this is the genealogy of them that went up with me from Babylon--The number given here amounts to 1754. But this is the register of adult males only, and as there were women and children also (Ezr 8:21), the whole caravan may be considered as comprising between six thousand and seven thousand.
ezr 8:15HE SENDS TO IDDO FOR MINISTERS FOR THE TEMPLE SERVICE. (Ezr 8:15-20)
I gathered them together to the river that runneth to Ahava--This river has not been ascertained. It is probable that the Ahava was one of the streams or numerous canals of Mesopotamia communicating with the Euphrates [CyclopÃ&brvbr;dia of Biblical Literature]. But it was certainly in Babylonia on the banks of that stream; and perhaps the place appointed for general rendezvous was in the neighborhood of a town of the same name. The emigrants encamped there for three days, according to Oriental custom, while the preparations for the departure were being completed and Ezra was arranging the order of the caravan.
I . . . found there none of the sons of Levi--that is, the ordinary Levites. Notwithstanding the privilege of exemption from all taxes granted to persons engaged in the temple service, none of the Levitical tribes were induced to join the settlement in Jerusalem; and it was even not without difficulty Ezra persuaded some of the priestly families to accompany him.
ezr 8:16then sent I for Eliezer . . . with commandment unto Iddo the chief--Ezra sent this deputation, either by virtue of authority which by his priestly character he had over the Levites, or of the royal commission with which he was invested. The deputation was despatched to Iddo, who was a prince or chief of the Nethinims--for the Persian government allowed the Hebrews during their exile to retain their ecclesiastical government by their own chiefs, as well as to enjoy the privilege of free worship. Iddo's influence procured and brought to the camp at Ahava thirty-eight Levites, and two hundred twenty Nethinims, the descendants of the Gibeonites, who performed the servile duties of the temple.
ezr 8:21A FAST PROCLAIMED. (Ezra 8:21-36)
Then I proclaimed a fast there--The dangers to travelling caravans from the Bedouin Arabs that prowl through the desert were in ancient times as great as they still are; and it seems that travellers usually sought the protection of a military escort. But Ezra had spoken so much to the king of the sufficiency of the divine care of His people that he would have blushed to apply for a guard of soldiers. Therefore he resolved that his followers should, by a solemn act of fasting and prayer, commit themselves to the Keeper of Israel. Their faith, considering the many and constant perils of a journey across the Bedouin regions, must have been great, and it was rewarded by the enjoyment of perfect safety during the whole way.
ezr 8:24Then I separated twelve of the chief of the priests . . . and weighed unto them the silver, &c.--The custody of the contributions and of the sacred vessels was, during the journey, committed to twelve of the chief priests, who, with the assistance of ten of their brethren, were to watch closely over them by the way, and deliver them into the house of the Lord in Jerusalem. The treasures in silver and gold, according to the value of the Babylonian talent, amounted to about Â£515,000 sterling.
ezr 8:27two vessels of fine copper, precious as gold--Almost all commentators agree in maintaining that the vessels referred to were not made of copper, but of an alloy capable of taking on a bright polish, which we think highly probable, as copper was then in common use among the Babylonians, and would not be as precious as gold. This alloy, much esteemed among the Jews, was composed of gold and other metals, which took on a high polish and was not subject to tarnish [NOYES].
ezr 8:31we departed from the river of Ahava on the twelfth day of the first month--Computing from the time of their setting out to the period of their arrival, they occupied about four months on the way. Their health and security were marvellous during so long a journey. The pilgrim-caravans of the present day perform long journeys through the wildest deserts of the East under the protection of a firman from the Porte, and an escort of soldiers. But for a large body, composed as that of Ezra--of some thousands of men, women, and children, unaccustomed to travel, undisciplined to order, and without military strength, and with so large an amount of treasure tempting the cupidity of the marauding, plundering tribes of the desert--to accomplish a journey so long and so arduous in perfect safety, is one of the most astonishing events recorded in history. Nothing but the vigilant care of a superintending Providence could have brought them securely to their destination.
ezr 8:33Now on the fourth day was the silver . . . weighed in the house of our God--The first three days after their arrival in Jerusalem were undoubtedly given to repose; on the next, the treasures were weighed and handed over to the custody of the officiating priests of the temple. The returned exiles offered burnt offerings, and Ezra delivered the royal commission to the satraps and inferior magistrates; while the Levitical portion of them lent all the assistance they could in performing the additional work which the arrival of so many new worshippers occasioned.