“For there is one essence, one goodness, one power, one will, one energy, one authority, one and the same, I repeat, not three resembling each other. But the three subsistences have one and the same movement. For each one of them is related as closely to the other as to itself: that is to say that the Father, the Son, and the Holy Spirit are one in all respects, save those of not being begotten, of birth and of procession. But it is by thought that the difference is perceived. For we recognise one God: but only in the attributes of Fatherhood, Sonship, and Procession, both in respect of cause and effect and perfection of subsistence, that is, manner of existence, do we perceive difference.”
Saint John of Damascus
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