“My son, when you come to serve God, prepare your soul for temptation.” – Ecclus. (Sirach) 2:1
St. Francis de Sales, whose feast we celebrate on 24th January (29th January in the Extraordinary Form) in his book Introduction to the Devout Life, explains what you should do when you are initially tempted.
So soon as you feel yourself anywise tempted, do as our little children when they see a wolf or a bear in the mountains. Forthwith they run to the protection of their father or mother, or at least cry out for help. Do you fly in like manner to God, claiming His compassion and succour,—it is the remedy taught us by our Lord Himself: “Pray that ye enter not into temptation.”
If, nevertheless, the temptation persists or increases, hasten in spirit to embrace the holy Cross, as though you beheld Jesus Christ Crucified actually Present. Make firm protests against consenting, and ask His Help thereto; and, so long as the temptation lasts, do you persist in making acts of non-consent. But while making these acts and these protests, do not fix your eyes on the temptation—look solely on Our Lord, for if you dwell on the temptation, especially when it is strong, your courage may be shaken.
Divert your mind with any right and healthy occupation, for if that takes possession and fills your thoughts, it will drive away temptation and evil imaginations.
St Francis de Sales also advises us to keep the mind fixed steadily on The Cross of Christ, praying constantly, even if we are able to utter no more than brief aspirations under strong temptation. His description of how lovers constantly think of their beloved is especially apt in keeping temptation at bay and in love of God.
Do you then, my daughter, aspire continually to God, by brief, ardent upliftings of heart; praise His Excellence, invoke His Aid, cast yourself in spirit at the Foot of His Cross, adore His Goodness, offer your whole soul a thousand times a day to Him, fix your inward gaze upon Him, stretch out your hands to be led by Him, as a little child to its father, clasp Him to your breast as a fragrant nosegay, upraise Him in your soul as a standard. In short, kindle by every possible act your love for God, your tender, passionate desire for the Heavenly Bridegroom of souls. Such is ejaculatory prayer, as it was so earnestly inculcated by St. Augustine upon the devout Proba; and be sure, my daughter, that if you seek such nearness and intimacy with God your whole soul will imbibe the perfume of His Perfections. Neither is this a difficult practice, – it may be interwoven with all our duties and occupations, without hindering any; for neither the spiritual retreat of which I have spoken, nor these inward upliftings of the heart, cause more than a very brief distraction, which, so far from being any hindrance, will rather promote whatever you have in hand. When a pilgrim pauses an instant to take a draught of wine, which refreshes his lips and revives his heart, his onward journey is nowise hindered by the brief delay, but rather it is shortened and lightened, and he brings it all the sooner to a happy end, pausing but to advance the better.
And a few more words from the Saint on prayers of aspiration to help divert our mind from temptation and grow in love.
Sundry collections of ejaculatory prayer have been put forth, which are doubtless very useful, but I should advise you not to tie yourself to any formal words, but rather to speak with heart or mouth whatever springs forth from the love within you, which is sure to supply you with all abundance. There are certain utterances which have special force, such as the ejaculatory prayers of which the Psalms are so full, and the numerous loving invocations of Jesus which we find in the Song of Songs. Many hymns too may be used with the like intention, provided they are sung attentively. In short, just as those who are full of some earthly, natural love are ever turning in thought to the beloved one, their hearts overflowing with tenderness, and their lips ever ready to praise that beloved object; comforting themselves in absence by letters, carving the treasured name on every tree;–so those who love God cannot cease thinking of Him, living for Him, longing after Him, speaking of Him, and fain would they grave the Holy Name of Jesus in the hearts of every living creature they behold. And to such an outpour of love all creation bids us – nothing that He has made but is filled with the praise of God, and, as says St. Augustine, everything in the world speaks silently but clearly to the lovers of God of their love, exciting them to holy desires, whence gush forth aspirations and loving cries to God.