From the Angelic Doctor...
"A real relation in God can be based only on action. Such relations are not based on the actions of God according to any extrinsic procession, forasmuch as the relations of God to creatures are not real in Him. Hence, it follows that real relations in God can be understood only in regard to those actions according to which there are internal, and not external, processions in God."
-- Saint Thomas Aquinas (1225-74)