I believe the song is about how christianity has evolved from a peacful ideology into an excuse for many of the ills in the world. In the 1st chorus the songwriter takes the form of spokesperson for the religion, sees it's virtuos side (Jerusalam bells, choirs singing) requests us to continue in this vein(Be my mirror/sword/shield& missionary) and then bemoans that it has evolved wrongly (never an honest word). The 2nd chorus complains "St Peter won't call my name" (because of this evolution) and the 3rd chorus is a plea to hear the virtuos side, assuring us that if we do St Peter will "call my name". The verses illustrate some of the wrongs done in the name of christianity. Eg the treatment of french people under the reign of Louis xvi where the aristocracy and wealthy clergy abandoned the needs of their people. There are also references to the acknowledgement of how the foundations of christianity have been poluted ("my castles stand upon pillars of salt/sand"). In conclusion I feel it is a cry for christianity to return to it's original form of peace and love for everyone or face the consequences! Vida La Vida or Death and all his friends may translate as (spanish?) Live the (virtuos) Life or accept the dark alternative.