"The homoousion, then ... is of staggering significance. It crystallizes the conviction that while the incarnation falls within the structure of our spatio-temporal humanity in this world, it also falls within the Life and Being of God. Jesus Christ is thus not a mere symbol, some representation of God detached from God, but God in his own Being and Act come among us, expressing in our human form the Word which he is eternally in himself, so that in our relations with Jesus Christ we have to do directly with the ultimate reality of God. As the epitomized expression of that fact, the homoousion is the ontological and epistemological linchpin of Christian theology. With it, everything hangs together; without it, everything ultimately falls apart." --Thomas F. Torrance (1913-2007)
Taken from Thomas F. Torrance, The Ground and Grammar of Theology. (Charlottesville, VA: University Press of Virginia, 1980), pp. 160-161.
Torrance served for 27 years as professor of Christian Dogmatics at New College, Edinburgh in the University of Edinburgh.