Notes on the Bible, by Albert Barnes, , at sacred-texts.com
The festival lasted from the 15th day of the 7th month to the first. The 22nd day was a day of solemn observance Neh 8:18. One day seems to have been allowed the people for rest; and then the work of repentance, for which they had shown themselves ready Neh 8:9, was taken in hand, and a general fast was proclaimed.
The Septuagint and the Vulgate remove the comma after "stairs." By the "stairs (or scaffold) of the Levites" is to be understood as an elevated platform from which they could the better address and lead the people (compare Neh 8:4).
Stand up - The people had knelt to confess and to worship God Neh 9:3. They were now to take the proper attitude for praise. Compare throughout the margin reference.
The host of heaven worshippeth thee - i. e the angels. See Kg1 22:19; Psa 103:21.
In their rebellion - The Septuagint and several maunscripts have "in Egypt" (the words in the original differing by one letter only), and translate - "And appointed a captain to return to their bondage in Egypt." Compare the margin reference. The appointment of a leader is regarded here as made, whereas we are only told in the Book of Numbers that it was proposed.
Thou didst divide them into corners - i. e., parts of the holy land; or as some prefer "thou didst distribute them on all sides."
Became fat. - i. e., "grew proud," or "wanton" - a phrase only occurring here, in the margin reference, and in Jer 5:28.
Delighted themselves - Rather, "luxuriated." The word in the original does not occur elsewhere; but cognate terms make the sense clear.
Slew thy prophets - Compare Kg1 18:4; Kg1 19:10; Ch2 24:21. Jewish tradition further affirms that more than one of the great prophets (e. g., Isaiah, Jeremiah, and Ezekiel) were martyred by their countrymen.
Thou gavest them saviours - See Jdg 3:15 etc.
Seal unto it - The exact force of the phrase used is doubtful; but its general sense must be that the classes named took part in the sealing. It was usual in the East to authenticate covenants by appending the seals of those who were parties to them (see Jer 32:10).