This is a hymn from Bob Dufford SJ, and we used to use the first verse and refrain as the the “Lamb of God” when we used his Mass. It had an odd unbalancing effect because, for some reason, it was taken to with surprising vigor and sung more enthusiastically than anything else, so we had a celebration where the high point was the Agnes Dei.
OCP has sample sheet music here and you can hear a sample and buy the music here. They do it very slowly. This church is doing it more the speed we did it and this piano version fairly rockets along. The whole original can be heard here.
If you get beyond verse one and the chorus the text is for the Easter season.
My backing is a render of an old MIDI I made to try to learn the whole song.
1. Behold the Lamb of God, Behold the Lamb of God,
who carries our burden, who knows our pain,
who bears the sins of the world.
Behold the Lamb of God, Behold the Lamb of God,
Jesus, Jesus is the Lamb of God.
2. Surely he has borne our grief
and carried the sorrows of us all.
Struck down in our stead, rejected and scorned,
and by his wounds we are healed.
3. Father, forgive them; they do not understand.
They do not understand what they do.
4. The kingdom of this world
has become the kingdom of Christ,
and he shall reign for endless days.
Worthy is the Lamb.
© Robert Dufford 1985.