Donner des réponses. - Lingua Latina

I have been trying to work out the sentence construction in a couple of lines from the medieval hymn "The Gradual of Eleanor of Brittany" (also called "Orbis Factor"). There is a line which goes " Patrem tuum teque flamen utrorumque" , I am wondering why patrem tuum is in the accusative?  Could it be dependent on the next line - "Deum scimus unum atque trinum esse" ?  Is it a translator's mistake?