Hmmm... I thought I might be able to clear up a bit of the Spanish side of this thread, but I am confused about what meaning of "goodwill" hollisr is actually referring to.
I might be desperately wrong, but for me, "goodwill" in English is a synonym for "charity", i.e. an organisation or group that works to help the poor or otherwise deprived. In Spanish we refer to these as "obra benéfica / de beneficencia", and sometimes as "organización sin ánimo de lucro" (non-profit). If I'm wrong about the meaning of the English "goodwill", then obviously this doesn't apply to hollisr's question, so please don't pay any attention.
Regarding "voluntad", that word merely means "will", i.e. an inclination or determination to do something. "Buena voluntad", therefore, means you are well disposed to do something. "Et in terra pax hominibus bonae voluntatis", which Faldage quoted from Luke, is "y en la tierra paz a los hombres de buena voluntad", I'm not sure what is the prevalent translation of this phrase in English, but it would be a functional equivalent in this case.
"Voluntad", however, can never be taken to mean "volunteering", although the two are related. For "volunteering" we would say "ser voluntario", or "hacer trabajo voluntario", or something like that.
I hope this was not too tangled.
Marianna
