Lukas 17:10

Also auch ihr; wenn ihr alles getan habt, was euch befohlen ist, so sprechet: Wir sind unnütze Knechte; wir haben getan, was wir zu tun schuldig waren.

So likewise ye, when ye shall have done all those things which are commanded you, say, We are unprofitable servants: we have done that which was our duty to do.