אִֽם־יִשְׁמְר֬וּ בָנֶ֨יךָ ׀ בְּרִיתִי֮ וְעֵדֹתִ֥י ז֗וֹ אֲלַ֫מְּדֵ֥ם גַּם־בְּנֵיהֶ֥ם עֲדֵי־עַ֑ד יֵ֝שְׁב֗וּ לְכִסֵּא־לָֽךְ׃
Kung iingatan ng iyong mga anak ang Aking tipan at ang Aking patotoo na ituturo Ko sa kanila, ang kanilang mga anak man ay uupo magpakailanman sa iyong trono.”
Malbim
and for the sake of Jerusalem, the city which I have chosen. As it is written “…also their sons will sit on your throne forever. For the Lord has chosen Zion; He desired it for His habitation.” (Tehillim 132:12-13) Through the choosing of Zion it will be seen that David’s throne will remain there because he built Zion, as I explained in my commentary on Tehillim.
Malbim
But will God indeed dwell on the earth – This is adding another argument to what I said in explanation of Tehillim 89 that the Holy Temple and kingship of the house of David are each causes of one another. Gd chose to rest His Presence on the house which was chosen through the merit of David, and after He chose Zion and established His Presence there He once again exerted His providence to maintain the house of David in the merit of the Temple, as it says “Arise, O Lord, to Your resting place…For the sake of David Your servant…” (Tehillim 132:8-10) This teaches that David’s merit caused the Divine Presence to dwell in the Temple. Then it says further on “…also their sons will sit on your throne forever. For the Lord has chosen Zion…” (Tehillim 132:12-13) which teaches that Gd saw fit to sustain the kingship of the house of David because He had chosen Zion. This is what our verse means – please affirm Your word which You spoke to David because ‘God will indeed dwell on the earth’. From this moment it is real and believable that Gd will have an established dwelling place on earth, and this is dependent on the kingship of the house of David. ...
Ibn Ezra
The word your plagues has elements of the singular form and of the plural form, in combination. Compare, “this testimonies of mine that I shall teach them” [Psalms 132: 12].