In a 1984 article in the journal Mid-Stream , Leslie Newbigin insisted that the basis of the demand for church unity is “the triune nature and action of God.”
He gave this stirring explanation: “Because God the Father has given his Son tous, and in the incarnate Lord Jesus Christ he both freely declared his nature and effectedhis purpose, and because he continues by the work of the Spirit to disclosethat nature and effect that purpose from generation to generation, from race to race,by drawing men and women to him, we are under the obligation of love and faithfulnessto bring every thought, every activity, and every visible form or organizationinto subjection to him. There is one God and one mediator between God andhuman beings in whom he wills to reconcile all things to himself. Therefore thosewho are the bearers of his mission must themselves be reconciled” (4).
At the same time, he rejected any hint that this Trinitarian account of unity could be set against a Christocentric account: “It is only if Jesus is indeed supreme above every other name or power or principle orprogram that the unity of his people is really essential. He is, in simple fact, the onein whom the Father purposes to unite all people, all nations and all created beings,making peace by the blood of his Cross. Because this is so it is of the very essence ofthe Church that it should be onea sign and firstfruit and instrument of that unity” (5).
“The Basis and Forms of Unity,” Mid-Stream 23 (1984) 1-12.