Nehemiah 8:5 "Ezra opened the book. All the people could see him because he was standing above them; and as he opened it, the people all stood up."
The date was October 8, 445 BC (the 1st day of the 7th month of the Jewish calendar). Under the prophet (and scribe) Ezra, a second wave of Israelites was returning from exile in Babylon. They had been released from exile by the Persian King, Cyrus the Great, in March 538 BC, after they had been taken into exile by the Neo-Babylonian/Chaldean King Nebuchadnezzar after he had destroyed Jerusalem in 586 BC.
Ezra was reading from the Book of the Law that Hilkiah the high priest found in the temple during the reign of King Josiah (640-609 BC). The occasion was the New Year's Day of the civil calendar, celebrated as the Feast of Trumpets, with cessation of labor and a sacred assembly.
A lot of what we do in worship has its origin in events from the Bible. When we sing the Glory to God we remember the angels who sang at Jesus' birth. When we sing Psalms we are using the same "hymnal" as people did during Old Testament times. When we confess our sins, we are doing what it says we should do throughout the Bible.