Remember what Yggdrasill said: "You have not the right".To wield the Eternal Sword he must defeat Kratos because he is the seal to Origin. He has to courage to face Kratos and break the seal and make a pact with the Summon Spirit Origin. Force the Eternal Sword into a blade and create a new bond with it that's what Origin told him. I've Kratos didn't search for the items to make the Eternal Ring, Lloyd will never be able to wield it. In the begin of the game Dirk said that I've Lloyd is truly grow up he got something special for him. Kratos gives his sword to Lloyd as well, the Material Blade is born. The Material Blade becomes the Eternal Sword, in the Tower Salvation Lloyd obtain the title of Eternal Swordsman. With the Eternal Sword, he can bring the 2 worlds back to normal and awake the Giant Kharlan Tree.
Falcon's Crest
How to see this great attack with the Eternal Sword:
You must equip the Material Blade.
Press: X and then A and B it's the easiest way.
I'll show you....Divine Justice!