Either in reverence to God's word, of which see Numbers 11:32 Judges 3:20; or that they might hear his words the more distinctly: or rather, because they observed that Ezra composed himself to prayer or thanksgiving; which is here generally declared, but doubtless was more particularly and largely expressed in that assembly, as appears by their answering Amen, Amen, to his prayer.
Related Commentaries of Nehemiah 8:5
Nehemiah 8:5
5 And Ezra opened the book in the sightb of all the people; (for he was above all the people;) and when he opened it, all the people stood up: