Share 'I need to find the title of this beautiful song...'

Oi guys! Do you know that feeling when you keep on spending hours and hours thinking about "What was the name of that song  I heard?". I do have this problem right now and I hope you will give me a handy by solving it :) 2 or 3 days ago, at (dunno exactly) I heard a choir singing a song that really sounded like a spiritual (christian) chant. I can't remember anything of this song, but it must hav…