1)
Why does it say "u'Va'u v'Sha'arei ha'Ir ha'Zos"?
1.
Radak: They will enter and leave, like it says above (verse 19) "Malchei Yehudah will enter through it, and leave through it."
2.
Malbim: He promised them four matters. (a) Malchus Beis David will not cease. (b) Foreigners will not rule over them - "Ish Yehudah". (c) The city will not be destroyed - "v'Yashvah ha'Ir." Also refer to 17:26:1:1.
2)
Do the officers sit on David's throne?!
1.
Malbim: No. The kings sit on David's throne, and the officers ride on chariots and horses.
