FYI: Chapter III - The Spiritual Writings of Aikido
As previously stated, I don't know if the kotodama information came first, and I'm not sure that anyone else knows either.
I'm suprised that there was writing 4000 years ago. It's confusing to me since there is a well known "oral tradition" of the New Testiment which would have happened about 2000 years ago. But I'm no expert on China.