Ad te levavi – Introitus Dominica Prima Adventus.
Actually, by digging around to try to figure this one out, I found out that this was supposed to be last Sunday’s music. Psalm 25: 1-3:
I will lift up my soul to you, my God, and confide in you; I will not be ashamed, nor will my enemies mock me. For all those who wait for you will not be confounded.