“Christ cannot have human vicarage in the person of the tsar or high-priest.”

"Nihilism  On  A  Religious  Soil" (6 May 1907); it should be noted here that Berdyaev is here defining "theocracy" not in the sense as it is often used, of people ruling over other people, in claims of doing so by the commands of God, but rather defining it in terms of Christian anarchism — as a vigorous assertion of the right of no-one to rule over humans, save God.
Context: The new religious consciousness rises up against the nihilistic attitude towards the world and mankind. If a religious rebirth be possible, only then on this soil will there be the revealing of the religious meaning of secular culture and earthly liberation, the revealing of the truth about mankind. For the new religious consciousness the declaration of the will of God is together with this a declaration of the rights of man, a revealing of the Divine within mankind. We believe in the objective, the cosmic might of the truth of God, in the possibility according to God to guide the earthly destiny of mankind. This will be the victory of the true theocracy, whether over a false democratism, — the apotheosis of the quantitative collectivity of human wills, or so also over the false theocraticism, — all that apotheosis of the human will within Caesaropapism or Papocaesarism. Christ cannot have human vicarage in the person of the tsar or high-priest. He — is Himself the Tsar and High-Priest, and He will reign in the world. “Thy Kingdom come, Thy Will be done on earth, as it is in Heaven.”