Here is an excerpt from one of his letters translated from the original Spanish:
If we feel weak, let us rely on God, and we shall be strong: for those who confide in Him “shall take wings as eagles and not faint.” (Isaias XL. 31.) If we know not what to do, let us trust in our Creator, and He will be our Light; for, as Isaias says, “who is there amongst you that hath walked in darkness and hath no light? Let him hope in the name of the Lord, and lean upon his God.” (L. 10.) Holy Scripture also tells us: “They that trust in God shall understand the truth.” (Wisd. III. 9.) Let us place our hope in our heavenly Father when we are in trouble, and we shall be set free from it, as David, speaking in His name, says in the Psalms: (XC. 14.) “Because he hoped in me I will deliver him.” . . . . Believe me, God can overcome all our doubts and temptations.
Juan de Ávila, Letter XVII, reprinted in Letters of Blessed John of Avila, translated and selected from the Spanish by the Benedictines of Stanbrook ; with preface by the R.R. Abbot Gasquet. Published 1904 by Stanbrook Abbey, Burns &amp;amp;amp;amp; Oats in Worcester,London, p. 109 (bold added) (available for free at the Open Library at http://openlibrary.org/books/OL7253964M/Letters_of_Blessed_John_of_Avila).