It is a consequence of our sympathetic endowment that we revolt from inflicting pain on another, and even forego a certain satisfaction to self rather than be the occasion of suffering to a fellow creature.

Moved thus, we perform many obligations on the ground of the misery (not our own) accruing from their neglect.
A considerable portion of human virtue springs directly from this source.

If purely disinterested tendencies were withdrawn from the breast, the whole existence of humanity would be changed.

Society might not be impossible; there are races where mutual sympathy barely exists: but the fulfilment of obligations, if always dependent on a sense of self-interest, would fail where that was not apparent.

On the other hand, if we were on all occasions touched with the unhappiness to others immediately and remotely springing from our conduct--if sympathy were perfect and unfailing--we could hardly ever omit doing what was right.
(3) Our several Emotions or Passions may co-operate with Prudence and with Sympathy in a way to make both the one and the other more efficacious.
Prudence, in the shape of aversion to pain, is rendered more acute when the pain is accompanied with Fear.