but unto God the things that are God's

"What do emperors have to do with councils?"

St. John of Damascus, Commentary on a passage in St. Sophronius' The spiritual garden, in the "Ancient documentation and testimony of the Holy Fathers concerning images" appended to the First apology of St. John of Damascus against those who attack the divine images 16, in St. John of Damascus on the divine images, trans. David Anderson (Crestwood, NY:  St. Vladimir's Seminary Press, 1980), 48.  Cf.

We will obey you, O emperor, in those matters which pertain to our daily lives:  payments, taxes, tributes; these are your due and we will give them to you.  But as far as the government of the Church is concerned, we have our pastors, and they have preached the word to us; we have those who interpret the ordinances of the Church.  We will not remove the age-old landmarks which our fathers have set, but we keep the tradition we have received.

Second apology 12, p. 60.  Cf. also pp. 47, 53, 59, and 63.