You are now on the road, and you know how to proceed. But beware of enemies who will set themselves to obstruct you if they can. Nothing distresses them more than your desire and longing for the love of Jesus, and their whole purpose is to uproot this from your heart, and turn you back again to the love of earthly things. Your chief enemies are the bodily desires and foolish fears which the corruption of human nature stirs up in your heart, and which would stifle your desire for the love of God and take full possession of your heart. These are your deadliest enemies. There are also others, for evil spirits employ all their tricks to deceive you. But you have one remedy, as I told you before. Whatever they say, do not believe them; keep on your way, and desire nothing but the love of Jesus. Let your answer always be, 'I am nothing, I have nothing, I desire nothing but the love of Jesus.'"
(from The Ladder of Perfection, by Walter Hilton)