In Hosian theology, Binitarianism represents the mainstream Pneumatological view that God and Eliyahu are two distinct personalities forming a single godhead. Formalised by the Council of Auroria, the binitarian doctrine holds that God and the Spirit are coequal, pre-existing parts of the same Godhead. It is often expressed as the view that "... God is the Spirit and yet God is not the Spirit; and the Spirit is God, yet the Spirit is not God."
Mainstream Hosian binitarianism is homoiousian, holding the view expressed in the Aurorian Creed that Eliyahu and God share in a similar divine substance, as expressed by the tenet of the Creed that stipulates that Eliyahu is "... in His whole Substance like unto God." Though it also holds that the Spirit proceeded from God, Hosian binitarianism denies that the Spirit did at any point not exist and holds that He was always part of the Godhead: "In God and of God and from God".
Various alternative viewpoints arose when the Council of Auroria codified binitarianism as orthodox Hosian doctrine. One faction, led by Eudemos of Hobrazia, rejected the tenet that Eliyahu was a different person from God, while Ordius rejected the teaching that Eliyahu was in all respects the equal of God. These two founded rival churches, which occasionally refer to binitarianism as the Aurorian or Martinian (after St. Martinus of Augusta, the reported author of the Aurorian Creed) heresy.