Indeed no true and perfect human society can be conceived which is not governed by some supreme authority. Christ therefore must have given to His Church a supreme authority to which all Christians must render obedience. For this reason, as the unity of the faith is of necessity required for the unity of the church, inasmuch as it is the body of the faithful, so also for this same unity, inasmuch as the Church is a divinely constituted society, unity of government, which effects and involves unity of communion, is necessary jure divino.
--Pope Leo XIII, Satis Cognitum, On the Unity of the Church 1896.
(Note: jure divino= by divine law).
No one, therefore, unless in communion with Peter can share in his authority, since it is absurd to imagine that he who is outside can command in the Church.
They have not the heritage of Peter who have not the see of Peter, rent by their impious division. 