I cannot want it more — Self-Esteem

I cannot want it more－¹
I cannot want it less－
My Human Nature's fullest force
Expends itself on this.

And yet it nothing is ⁵
To him who easy owns－
Is Worth itself or Distance
He fathoms who obtains.

(F.1228/J.1301)

[1, 2] it, more, less:: self-esteem more or less owned by a person, hinted in line 8.
[3] Human Nature:: self-esteem is a human nature.
[5, 6] nothing, easy owns:: an arrogant man's self-esteem is nothing.
[8] fathoms:: probes, measures.
[7, 8] itself, fathoms:: a hint on self-esteem, self measure.