Pasolini's Il Vangelo secondo Matteo is one of the most memorable pieces of cinema I've ever seen. I just saw it for a second time, and what strikes me most is the soundtrack. The contrast of Bach's choral piece, St.Matthew's Passion, with Odetta's A Motherless Child and the mind-blowing excerpts of Missa Luba, combined with the cinematographic style literally make the film. Missa Luba is a Congolese take on Latin Mass, in which a choir underlays a solo voice - here's some recordings and notes on the compositions (gourd shaking is vital). The actual piece that Pasolini uses throughout the film is a child choir performance of 'Gloria', in particular the latter stages. If you haven't seen the film, you're missing out on the best biopic ever created.