Jamieson, Fausset and Brown on Ezra 7:6

6. This Ezra ... was a ready scribe in the law of Moses--The term "scribe" does not mean merely a penman, nor even an attorney well versed in forms of law and skilled in the method of preparing public or private deeds. He was a rabbi, or doctor, learned in the Mosaic law, and in all that related to the civil and ecclesiastical polity and customs of the Hebrew people. Scribes of this description possessed great authority and influence (compare Mt 23:25; Mr 12:28).

the king granted him all his request--left Babylon entrusted with an important commission to be executed in Jerusalem. The manner in which he obtained this office is minutely related in a subsequent passage. Here it is noticed, but with a pious acknowledgment of the divine grace and goodness which disposed the royal mind in favor of Ezra's patriotic objects. The Levites, &c., did not go at that time, but are mentioned here by anticipation.