This is a rendition of Dubois’ Adoramus Te.
It is taken from the Stations of the Cross devotions.
Here is the full text, of which this version excludes from Qui Passus:
Adoramus te, Christe, et benedicimus tibi,
quia per sanctam crucem tuam redemisti mundum.
Qui passus es pro nobis, Domine, Domine, miserere nobis.
We adore Thee, O Christ, And we bless Thee,Who by Thy Holy Cross hath redeemed the world.He who suffered death for us, O Lord, O Lord, have mercy on us.