The Imitation of Christ, by Thomas a Kempis, tr. by William Benham , at sacred-texts.com
"My Son, thou art not yet strong and prudent in thy love."
2. Wherefore, O my Lord?
3. "Because for a little opposition thou fallest away from thy undertakings, and too eagerly seekest after consolation. The strong lover standeth fast in temptations, and believeth not the evil persuasions of the enemy. As in prosperity I please him, so in adversity I do not displease.
4. "The prudent lover considereth not the gift of the lover so much as the love of the giver. He looketh for the affection more than the value, and setteth all gifts lower than the Beloved. The noble lover resteth not in the gift, but in Me above every gift.
5. "All is not lost, though thou sometimes think of Me or of My saints, less than thou shouldest desire. That good and sweet affection which thou sometimes perceivest is the effect of present grace and some foretaste of the heavenly country; but hereon thou must not too much depend, for it goeth and cometh. But to strive against the evil motions of the mind which come to us, and to resist the suggestions of the devil, is a token of virtue and great merit.
6. "Therefore let not strange fancies disturb thee, whencesoever they arise. Bravely observe thy purpose and thy upright intentions towards God. It is not an illusion when thou art sometimes suddenly carried away into rapture, and then suddenly art brought back to the wonted vanities of thy heart. For thou dost rather unwillingly undergo them than cause them; and so long as they displease thee and thou strivest against them, it is a merit and no loss.
7. "Know thou that thine old enemy altogether striveth to hinder thy pursuit after good, and to deter thee from every godly exercise, to wit, the contemplation of the Saints, the pious remembrance of My passion, the profitable recollection of sin, the keeping of thy own heart, and the steadfast purpose to grow in virtue. He suggesteth to thee many evil thoughts, that he may work in thee weariness and terror, and so draw thee away from prayer and holy reading. Humble confession displeaseth him, and if he were able he would make thee to cease from Communion. Believe him not, nor heed him, though many a time he hath laid for thee the snares of deceit. Account it to be from him, when he suggesteth evil and unclean thoughts. Say unto him, 'Depart unclean spirit; put on shame, miserable one; horribly unclean art thou, who bringest such things to mine ears. Depart from me, detestable deceiver; thou shalt have no part in me; but Jesus shall be with me, as a strong warrior, and thou shalt stand confounded. Rather would I die and bear all suffering, than consent unto thee. Hold thy peace and be dumb; I will not hear thee more, though thou plottest more snares against me. The Lord is my light and my salvation: whom then shall I fear? Though a host of men should rise up against me, yet shall not my heart be afraid. The Lord is my strength and my Redeemer.'(1)
8. "Strive thou like a good soldier; and if sometimes thou fail through weakness, put on thy strength more bravely than before, trusting in My more abundant grace, and take thou much heed of vain confidence and pride. Because of it many are led into error, and sometimes fall into blindness well-nigh irremediable. Let this ruin of the proud, who foolishly lift themselves up, be to thee for a warning and a continual exhortation to humility."
(1) Psalms xxvii. 1-3; xix. 14.