Holiness, like prayer (which is indeed part of it), is something that, though Christians have an instinct for it through their new birth, as we shall see, they have to learn in and through experience. As Jesus "learned obedience from what he suffered" (Heb. 5:8)-learned what obedience requires, costs and involves through the experience of actually doing His Father's will up to and in His passion-so Christians must, and do, learn prayer from their struggles to pray and holiness from their battles for purity of heart and righteousness of life. Talented youngsters who go to tennis school in order to learn the game soon discover that the heart of the process is not talking about tactics but actually practicing serves and strokes, thus forming new habits and reflexes, so as to iron out weaknesses of style. The routine, which is grueling, is one of doing prescribed things over and over again on the court, against a real opponent, in order to get them really right. Prayer and holiness are learned in a similar way as commitments are made, habits are formed and battles are fought against a real opponent (Satan, in this case), who with great cunning plays constantly on our weak spots. (That these are often what the world sees as our strong points is an index of Satan's resourcefulness: presumptuous self-reliance and proud overreaching on our part serve his turn just as well as do paralyzing timidity, habits of harshness and anger, lack of discipline, whether inward or outward, evasion of responsibility, lack of reverence for God and willful indulgence in what one knows to be wrong.) Satan is as good at judo throws as he is at frontal assaults, and we have to be on guard against him all the time.


J. I. Packer. Rediscovering Holiness: Know the Fullness of Life with God (pp. 14-15). Kindle Edition.