'Expert' in the Bible

This Ezra went up from Babylon; and he was a scribe, expert in the law of Moses which the Lord, the God of Israel, had given: and the king, moved by the Lord his God, gave him whatever he made request for.

This is the text of the letter King Artaxerxes gave to Ezra the priest and scribe, an expert in matters of the Lord’s commands and statutes for Israel:

Artaxerxes, king of kings, to Ezra the priest, an expert in the law of the God of heaven: Greetings.

I, King Artaxerxes, issue a decree to all the treasurers in the region west of the Euphrates River: Whatever Ezra the priest, an expert in the law of the God of heaven, asks of you must be provided promptly,