“A unity worshipped in Trinity and a Trinity summed up into unity”

Yes, let no one be lost, but let us all abide in one spirit, with one mind striving side by side for the faith of the gospel, being in full accord and of one mind armed with the shield of faith, loins girded about with truth, acknowledging one war alone, that against the Devil and his minions, fearing not those who can kill the body but cannot take the soul, but fearing the Lord of both soul and body; guarding the truth that we have received from our fathers, reverencing Father and Son and Holy Spirit; knowing the Father in the Son, the Son in the Holy Spirit, in which names we have been baptized, in which we believe, and under which we have been enlisted, dividing them before combining them and combining them before dividing them, and not regarding the three as a single individual (for they are not without individual reality nor do they comprise a single reality, as though our treasure lay in names and not in actual fact), but rather believing the three to be a single entity. For they are a single entity not in individual reality but in divinity, a unity worshipped in Trinity and a Trinity summed up into unity, venerable as one whole, as one whole royal, sharing the same throne, sharing the same glory, above space, above time, uncreated, invisible, impalpable, uncircumscribed, its internal ordering known only to itself, but for us equally the object of reverence and adoration, and alone taking possession of the Holy of Holies and excluding all of creation, part by the first veil, and part by the second. The first veil separates the heavenly and angelic realms from the Godhead, and the second, our world from that of the heavens.

St Gregory of Nazianzus