A.T. Robertson Commentary 1 Corinthians 12:26

"And whether one member suffereth, all the members suffer with it; or [one] member is honored, all the members rejoice with it." — 1 Corinthians 12:26 (ASV)

Suffer with it (συνπασχε). Medical term in this sense in Hippocrates and Galen. In N.T only here and Ro 8:17 (of our suffering with Christ). One of Solon's Laws allowed retaliation by any one for another's injuries. Plato (Republic, V, 462) says the body politic "feels the hurt" as the whole body feels a hurt finger.

Rejoice with it (συνχαιρε). This is fortunately true also. One may tingle with joy all over the body thanks to the wonderful nervous system and to the relation between mind and matter. See 13:6 for joy of love with truth.