Enlightenment and Trinity

Quoniam apud te est fons vitae et in lumine tuo videbimus lumen. Praetende misericordiam tuam scientibus te; et justitiam tuam iis qui recto sunt corde. Et enim post commemorationem coelestium beneficiorum, jure gratiae referuntur auctori Domino nostro Jesu Christo, qui fons vitae irriguus aeternae descendit in terras ut ariditatem nostri pectoris irrigaret. Idem est splendor gloriae Dei Patris, et imago substantiae ejus; et ideo in lumine ejus vero, quod illuminat omnem hominem venientem in hunc mundum, videbimus, inquit, Patrem; quia Deus lux est. Recte etiam dicitur: In lumine tuo videbimus lumen; secundum illud: Qui me videt, videt et Patrem meum. Apud te ergo, fons viate, praesentem videbimus Patrem. Sicut enim tu apud Patrem eras in principio Deus Verbum: ita apud te semper est Pater, qui in te est. Est enim apud ipsum, in quo est. Prophetatur autem adventus Domini Salvatoris, qui venturus in terram diceret, Ego et Pater unum summus; id est, unum sumus lumen, sicut unum nomen. Per luminis et nominis unitatem ambo unum sumus; immo Trinitas unum in unitate substantiae, sed distinctione uniuscujusque personae. Trinitas distinctionem significat personarum, unitas potestatem. Potest et ad Patrem dici: Quoniam apud te est fons vitae, id est, in te ex quo vita processit, erat Verbum, et semper erat, quia apud te erat. Omnia per ipsum et in ipso facta sunt; et ipse est vita universorum, et ipse te nobis manifestavit, ut corda hominum ad cognitionem tuae majestatis illuminentur. Sanctus Ambrosius Mediolanensis, Enarrationes In Psalmos, Psalmum XXXV

Because with you is the fount of life and in your light we see light. Reveal your mercy to those who know you, and your righteousness to those who are good in heart. 1 And after the commemoration of celestial benefactions, he rightfully gives thanks to our Lord and creator Jesus Christ, the watering fount of eternal life who descended to earth that he water our hearts. The same is the splendor of the glory of the Father, and the image of His substance, and there in His light, which enlightens all men coming into this world, 2 we see, He says, the Father, because God is light. Rightly he says, 'In your light we see light,' according to which, 'He who sees me, sees my Father.' 3 With you then is the fount of light, by which presence we see the Father. For as you were with the Father in the beginning, God the Word, so the Father is with you always, He who is in you. For certainly He is with himself, in which He is. And here prophesied is the coming of the Lord our Saviour, who coming to earth said, 'I and the Father are one,' 4 that is, we are one light, as we are one name. Through the unity of light and name we are both one, we are one trinity in unity of substance, but distinct in person. The Trinity signifies the distinction of person, and unity of power. He is able to say to the Father: Because with you is the fount of life, that is, in you from whom life proceeds, was the Word, and always was, because with you He was. Everything through Him and in Him was made, and He is the life of all things, 5 and He has manifested you to us, that the hearts of men with the knowledge of your majesty be illuminated. Saint Ambrose, Commentary on the Psalms, from Psalm 35 1. Ps 35, 10,11 2 Jn1.10 3 Jn 14.9 4 Jn 10.30 5 Jn 1. 3-4