1)
Why did he gather everyone, from Katan to Gadol, to make a Bris (verse 31)?
1.
'Rashi', Malbim (Melachim II, 23:2): He was afraid because the Sefer was found rolled to the curses, (Yuma 52b), which conclude "Eleh Divrei ha'Bris" (Devarim 28:69). [Shortly] after, Moshe gathered "Kulchem? Tapchem Nesheichem?. Le'avrecha bi'Vris" (ibid., 29:11). He said, also I will gather big and small!
2)
Why does it say that he read "Es Kol Divrei ha'Sefer ha'Bris"?
1.
Refer to 34:30:1:1.
