A scribe of the words of the commandments, the phrase seems emphatical, noting that he explained both the words and the things; for the Jews in the land of their captivity had in a great measure lost both their language, and the knowledge of God's commands, and therefore Ezra and his companions instruct them in both; of which see more on Nehemiah 8:8.
Related Commentaries of Ezra 7:11
Ezra 7:11
11 Now this is the copy of the letter that the king Artaxerxes gave unto Ezra the priest, the scribe, even a scribe of the words of the commandments of the LORD, and of his statutes to Israel.