If ye do not remember to be charitable,
ye are as dross,
which the refiners do cast out,
(it being of no worth)
and is trodden under foot of men.
My value to the Refiner is the value that I place on others. When I value others at some finite level, I am also valuing God, their Creator and the One who loved them first (1 Jn. 4: 19), at that level. That is what makes setting someone “at naught” so terribly debasing.
“There are no ordinary people. You have never talked to a mere mortal. [It] is immortals whom we joke with, work with, marry, snub, and exploit--immortal horrors or everlasting splendours.” –C.S. Lewis
Similarly, if I value God at a finite level (i.e. if my devotion to Him can be sold or de-prioritized), then I value all His children and creations at or below that level, including ironically, myself. To increase my value, I must increase the value that I place on others and on God.
I am commanded to love God (i.e. recognize God's infinite value) by loving (valuing at infinite) others, and to love myself as I love others. Acting in accordance with the infinite value of self, others, and God is the essence of the Gospel (Matt. 22: 37-40).