Here is a favorite prayer of St. Thomas Aquinas -- for a holy life. It was said that he prayed this every day before the image of Christ:
Grant me, O merciful God, that what is pleasing to Thee I may ardently desire, prudently examine, truthfully acknowledge, and perfectly accomplish for the praise and glory of Thy name.
Ordain, O my God, my whole life, and what Thou requirest that I should do, grant me to know it and to fulfill as is meet and profitable to my soul.
Give me Thy grace, O Lord my God, that I may not fail in prosperity or in adversity, avoiding pride in the former and discouragement in the latter.
May I rejoice in nothing but what leads to Thee, grieve for nothing but what turns away from Thee. May I wish to please or displease n one but Thee.
May I despise, O Lord, all transitory things, and prize only that which is eternal. May I shun ant joy that is without Thee, nor wish for anything outside of Thee.
May I delight in any work taken up for Thee, and tire of any rest which is without Thee. Grant me, O my God, to direct my heart toward Thee, and in my failings constantly grieve, with the purpose of a amendment.
Make me, O Lord, my God, obedient without contradiction, poor without depression, chaste without corruption patient without murmuring, humble without pretence, cheerful without dissipation, mature without dullness, prompt without levity, fearing Thee without despair, truthful without duplicity, doing good without presumption, correcting my neighbor without haughtiness, and edifying him by word and example without hypocrisy.
Give me, O Lord God, a watchful heart, which no curious thought will turn away from Thee; a noble heart, which no unworthy affection will drag down; a righteous heart, which no irregular intention will twist aside; a firm heart, which no tribulation will break; a free heart, which no violent affection will claim for itself.
Grant me finally, O Lord my God, science in knowing Thee, diligence in seeking Thee, wisdom in finding Thee, a conduct pleasing to Thee, a perseverance trustfully awaiting Thee, and a confidence finally embracing Thee. May I endure Thy punishments by penitence; profit by Thy benefits by grace in this world, and enjoy Thy blessedness by glory in the next; Who livest and reignest, true God, forever and ever. Amen
St. Thomas Aquinas Online
- Saint Thomas Aquinas Stanford Enyclopedia of Philosophy
- Saint Thomas Aquinas Catholic Enyclopedia 
- Thomas Aquinas' works in English courtesy of the Dominican friars of the Priory of the Immaculate Conception at the Dominican House of Studies in Washington, D.C.
Readings and studies of St. Thomas Aquinas
My very first introduction to The Doctor was by Peter Kreeft's A Summa of the Summa, by way of my dad, featuring a broad selection of his philosophical work along with Kreeft's commentary.
A few years ago I did a poll/post on introductions and studies of St. Thomas Aquinas for beginners or newcomers (and delving into the Summa from time to time is a good reminder that I'm exactly that). Here are some recommendations that were offered on my blog and elsewhere:
- Timothy McDermott’s Summa Theologiae: A Concise Translation
- Fritz Bauerschmidt’s Holy Teaching: Introducing the ‘Summa Theologiae’ of St. Thomas Aquinas
- Aquinas and His Role in Theology, by Marie-Dominique Chenu.
- A Guide to St. Thomas Aquinas, by Joseph Peiper.
- The Christian Philosophy of St. Thomas Aquinas, by Etienne Gilson.
- A Companion to the Summa, by Walter Farrell, OP. [Online text].
- St. Thomas Aquinas: Selected Writings, by Ralph MacInerney. [Also Dr. MacInerney's online lectures on Aquinas].
- A First Glance at St. Thomas Aquinas: A Handbook for Peeping Thomists, by Ralph MacInerney.
- G.K. Chesterton's The Dumb Ox, of which Etienne Gilson remarked: "I consider it as being without possible comparison the best book ever written on St. Thomas."