Lyric discussion by mithgil 

Cover art for Deus Ibi Est lyrics by Isobel Campbell and Mark Lanegan

The chorus is actually from a hymn, specifically the first line of each verse. Specifically, the line is:

"Ubi caritas et amor, Deus ibi est."

Caritas is charity, amor is love. Deus ibi est means 'God is there', and ubi is 'where'. So it means, "Where charity and love [are], God is there."