1)
Why does he assume that He will return to keep us alive?
1.
Rashi: You promised so via Your Nevi'im.
2.
Radak: No one else can revive us from the death of Galus.
3.
Malbim: You cannot permanently eradicate us. Even if we would compare the body of the Jewish nation in Galus to dry, dead bones, You will revive this body - "Hine Ani Pose'ach Es Kivroseichem... Ami" (Yechezkel 37:12)
2)
Why does it say "v'Amecha Yismechu Vach"?
1.
Radak: After You revive us, Your nation will rejoice in You.
2.
Malbim: Your anger cannot last for generations, for then Your nation will rejoice in You - it says "Yashuv Hashem Lasus Alecha l'Tov" (Devarim 30:9)!
