This quest starts the conclusion of [The Scepter of the Shifting Sands] quest chain to open the Gates of Ahn'Qiraj. Anachronos will only offer this quest after completing the [Blue Scepter Shard], [Green Scepter Shard] and [Red Scepter Shard] forks.
A thousand years has passed and just as it was fated, one stands before me. One who shall lead their people to a new age.
The Old God trembles, <name>. Oh yes, it fears your faith. Shatter the prophecy of C'Thun.
It knows you come, champion - and with you comes the might of Kalimdor. You have only to let me know when you are prepared and I shall grant you the [The Scepter of the Shifting Sands].
The Scepter of the Shifting Sands is whole once more, <name>.
It must be you who uses the scepter. It must be you who heralds the next age of your people.
You must wait for the armies of the Horde and the Alliance to arrive in Silithus before you may ring the Scarab Gong.
I am ready, Anachronos. Please grant me the Scepter of the Shifting Sands.
Back in 1.9, the entire realm needed to complete a fetch quest and then wait 7 full days before the scepter bearer could bang the gong to start the 10 Hour War.
Now that the gates are permanently open, there is no waiting period. Simply fly over to the gong to accept the final quest,  Treasure of the Timeless One. It is no longer possible to bang the gong.
You will receive:
This is part of the conclusion to [The Scepter of the Shifting Sands] quest chain:
-  The Might of Kalimdor
-  Bang a Gong! (gate opening +10 hours)
-  Treasure of the Timeless One (after 10 hours)