On that day. See Nehemiah 12:44. The phrase seems to mean, in Nehemiah, "About that time." They read in the book of Moses. It is uncertain whether this was a casual reading, like that of Ezra's, recorded in Nehemiah 8:1-8, or whether it was the prescribed reading (Deuteronomy 31:11) at the time of the feast of tabernacles.
Therein was found written. See Deuteronomy 23:3-5. It seems to be implied that the nation at large had no knowledge of the law, except that which they derived from the occasional public reading of the Pentateuch, or portions of it.
Copies of the law were extremely scarce; and even if an ordinary Jew possessed one, he would not have been able to understand it (comp. above, Nehemiah 8:8).