Board Thread:Naruto Discussions/@comment-29752445-20160826022014/@comment-25122992-20160826205309

Well, I can give the exact info where Hagoromo states this. It's the end of the chapter 670 and it's adaptation in the 420-th episode of Shippuden (also in the end). There, Hagoromo stated he saw the new possibilities in Asura's way of life, thus, inspired by his bonds, he has split the Juubi's chakra into 9 Tailed Beasts in his hopes that cooperation is the true power.