In 1727, I read Mr. Law’s ‘Christian Perfection,’ and ‘Serious Call,’ and more explicitly resolved to be all devoted to God, in body, soul, and spirit. In 1730 I began to be homo unius libri [a man of one book] to study (comparatively) no book but the Bible. I then saw, in a stronger light than ever before, that only one thing is needful, even faith that worketh by the love of God and man, all inward and outward holiness; and I groaned to love God with all my heart, and to serve Him with all my strength.
— John Wesley, Journal (for more quotes along this line, see: HOW MR. WESLEY WAS LED INTO THE LIGHT OF FULL SALVATION).
To candid, reasonable men, I am not afraid to lay open what have been the inmost thoughts of my heart. I have thought, I am a creature of a day, passing through life as an arrow through the air. I am a spirit come from God, and returning to God: Just hovering over the great gulf; till, a few moments hence, I am no more seen; I drop into an unchangeable eternity! I want to know one thing, — the way to heaven; how to land safe on that happy shore. God himself has condescended to teach the way: For this very end he came from heaven. He hath written it down in a book. O give me that book! At any price, give me the book of God! I have it: Here is knowledge enough for me. Let me be homo unius libri. Here then I am, far from the busy ways of men. I sit down alone: Only God is here. In his presence I open, I read his book; for this end, to find the way to heaven. Is there a doubt concerning the meaning of what I read? Does anything appear dark or intricate? I lift up my heart to the Father of Lights: — “Lord, is it not thy word, ‘If any man lack wisdom, let him ask of God?’ Thou ‘givest liberally, and upbraidest not.’ Thou hast said; ‘If any be willing to do thy will, he shall know.’ I am willing to do, let me know, thy will.” I then search after and consider parallel passages of Scripture, “comparing spiritual things with spiritual.” I meditate thereon with all the attention and earnestness of which my mind is capable. If any doubt still remains, I consult those who are experienced in the things of God; and then the writings whereby, being dead, they yet speak. And what I thus learn, that I teach.
— From the “Preface” to the Standard Sermons