Isaiah 51:11

Therefore the redeemed of the LORD shall return, and come with singing unto Zion; and everlasting joy shall be upon their head: they shall obtain gladness and joy; and sorrow and mourning shall flee away.

Therefore the redeemed of the Lord shall return - (.) "Therefore" - assurance of faith; or else the answer of Yahweh corresponding to their power. As surely as God redeemed Israel out of Egypt, He shall redeem them from Babylon, both the literal in the age following, and the mystical in the last ages (Revelation 18:20). There shall be a second exodus (Isaiah 11:11; Isaiah 27:12).

Come with singing - image from the custom of singing on a journey when a caravan is passing along the extended plains in the East.

Everlasting joy (shall be) upon their head - (.)

Sorrow and mourning shall flee away - (.)