In contemplating the holiness of God man develops more quickly than he does in his ability to conform his life to the commandments. Hence the impression that the distance between us and God continually increases. (page 22)
In other words we experience the holiness of God more easily than we are able to become holy ourselves. That's why it's so easy to get the impression that we are stagnant or even moving backwards in our spiritual life; the mysterious apprehension of God makes us more and more aware of our littleness and distance. But all of this is an optical illusion of the eye of the heart, as it were, because even this awareness is the work of the Holy Spirit that prays to the Father from within us.