The book is LIFE WITH GOD by Richard J. Foster
"A Spiritual Discipline is an intentionally directed action by which we do what we can do in order to receive from God the ability (power) to do what we cannot do by direct effort.
The Spiritual Disciplines in and of themselves have no merit whatsoever. They possess no righteousness, contain no rectitude. Their only purpose is to place us before God. Then the grace of God steps in and takes this simple offering of ourselves and creates out of it the kind of person who embodies the goodness of God.
The ability to do what needs to be done when it needs to be done is the true freedom in life.
Freedom comes not from the absence of restraint but from the presence of discipline.
Only the disciplined gymnast is free to score a perfect ten. Only the disciplined violinist is free to play Pangini's Caprices."