From the conclusion of St Augustine's De Trinitate:
O Lord our God, we believe in You, the Father and the Son and the Holy Spirit. For the Truth would not say, Go, baptize all nations in the name of the Father and of the Son and of the Holy Spirit, unless You were a Trinity. Nor would you, O Lord God, bid us to be baptized in the name of Him who is not the Lord God. Nor would the divine voice have said, Hear, O Israel, the Lord your God is one God, unless You were so a Trinity as to be one Lord God. And if You, O God, were Yourself the Father, and were Yourself the Son, Your Word Jesus Christ, and the Holy Spirit your gift, we should not read in the book of truth, God sent His Son; nor would You, O Only-begotten, say of the Holy Spirit, Whom the Father will send in my name; and, Whom I will send to you from the Father. Directing my purpose by this rule of faith, so far as I have been able, so far as You have made me to be able, I have sought You, and have desired to see with my understanding what I believed; and I have argued and labored much. O Lord my God, my one hope, hearken to me, lest through weariness I be unwilling to seek You, but that I may always ardently seek Your face. Do Thou give strength to seek, who has made me find You, and has given the hope of finding You more and more. My strength and my infirmity are in Your sight: preserve the one, and heal the other. My knowledge and my ignorance are in Your sight; where You have opened to me, receive me as I enter; where You have closed, open to me as I knock. May I remember You, understand You, love You. Increase these things in me, until You renew me wholly. I know it is written, In the multitude of speech, you shall not escape sin. But O that I might speak only in preaching Your word, and in praising You! Not only should I so flee from sin, but I should earn good desert, however much I so spoke. For a man blessed of You would not enjoin a sin upon his own true son in the faith, to whom he wrote, Preach the word: be instant in season, out of season. Are we to say that he has not spoken much, who was not silent about Your word, O Lord, not only in season, but out of season? But therefore it was not much, because it was only what was necessary. Set me free, O God, from that multitude of speech which I suffer inwardly in my soul, wretched as it is in Your sight, and flying for refuge to Your mercy; for I am not silent in thoughts, even when silent in words. And if, indeed, I thought of nothing save what pleased You, certainly I would not ask You to set me free from such multitude of speech. But many are my thoughts, such as You know, thoughts of man, since they are vain. Grant to me not to consent to them; and if ever they delight me, nevertheless to condemn them, and not to dwell in them, as though I slumbered. Nor let them so prevail in me, as that anything in my acts should proceed from them; but at least let my opinions, let my conscience, be safe from them, under Your protection. When the wise man spoke of You in his book, which is now called by the special name of Ecclesiasticus, We speak, he said, much, and yet come short; and in sum of words, He is all. When, therefore, we shall have come to You, these very many things that we speak, and yet come short, will cease; and You, as One, wilt remain all in all. And we shall say one thing without end, in praising You in One, ourselves also made one in You. O Lord the one God, God the Trinity, whatever I have said in these books that is of Yours, may they acknowledge who are Yours; if anything of my own, may it be pardoned both by You and by those who are Yours. Amen.