This phrase occurs in the Osashizu, The Divine Directions. It means that, for human beings, the mind alone is one’s own.
With human beings: the body is a thing lent by God, a thing borrowed. The mind alone is the truth of oneself.
Osashizu, June 1, 1889
The same meaning is indicated by the phrase “The mind alone is yours.” (Osashizu, February 14, 1889)
In explaining the human condition, the first thing that is brought up is the teaching of a “thing lent, a thing borrowed”—which teaches that human beings live by borrowing the body from God the Parent. The body is something lent by God, something borrowed from God the Parent, and as such it is not one’s personal possession. What this indicates is that God the Parent is enabling human beings to be alive at all.
It is in this context that Tenrikyo teaches that the “mind alone is the truth of oneself.” That the mind is ours means that we are allowed the free use of the mind by God the Parent. It is further taught, on the basis of this, that God the Parent is providing for all of us through reflecting the state of our mind as the state of our world. This is often referred to as the “blessing according to the state of mind,” an expression that encourages one to correct one’ s use of the mind.
With human beings: the body is a thing borrowed. The mind alone is yours. From just one mind, any kind of truth will appear daily.
Osashizu, February 14, 1889