The English mystical poet William Blake was also a first rate artist. Once, when asked to sketch a picture of man as he really is, Blake drew a picture of a child standing on the topmost rung of a ladder reaching for the moon and crying impatiently, "I want, I want!"
Blake felt that man is a creature of unfulfilled desires. He never is satisfied. "Man never is, but always to be blest." And so life is a series of rungs - infancy succeeded by youth and maturity or perhaps we should say adulthood: yesterday an infant dropping the toy in hand for the pretty bauble beyond his reach; today the adolescent wanting this and that; tomorrow the man reaching for the unattainable moon - or since it has been attained by a few, something beyond that.
A man does not cease to have wants when he becomes a Christian. Indeed God has some unfulfilled wants of his own for his children - their growth and development in lives of holiness. "This is the will of God, your sanctification."