Clash and a Promise (also styled "Lamenting and a Promise") is a BGM from Wild Arms. It is the second track that plays during the opening prologue. It features a choral accompaniment by students of Tokyo's Keio University sung in Latin. The lyrics are taken from "Alma Redemptoris Mater", a Marian hymn.
Alma Redemptoris Mater,
quae pervia caeli porta
Sweet Mother of the Redeemer,
the passage to the heavens, the gate
of the spirits of the dead...