Sometimes we are aware of the sin plaguing us, but attack it in the wrong way. Owen’s point in chapter three is that there is a way of mortifying that is utterly futile because it uses the wrong weapons.
God has told us to put to death the deeds of the flesh by the Spirit. If we approach this task by other means it’s like entering the battle with the wrong weapons.
This is the problem with so many of the attempts we make at conquering sin. We do it in our own strength, through fleshly will power. We may even use spiritual disciplines like fasting and prayer and taking vows. But if we look on those things as the ends and not the means, we will fail. Owen calls this will-worship and at its extreme, self-maceration! (Think of monks wearing rough garments and purposely afflicting their bodies to drive out sin.)
You can go to the extremes of self-denial and asceticism but those things are rusty, dull swords in the battle against the flesh.
Owen is writing in the 17th century so this is still a time of great tension between Catholics and Protestants. Many Puritans described Catholic practices with adjectives nobody uses anymore like popish and Romish. Here is an example:
“Neither will the natural popery that is in others do it. Men are galled with the guilt of a sin that has prevailed over them; they instantly promise to themselves and God that they will do so no more; they watch over themselves and pray for a season until this heat waxes cold and the sense of sin is worn off – and so mortification goes also, and sin returns to its former dominion.”
What is this “natural popery”? I think he is referring to the natural tendencies in our flesh to want to combat sin with the weapons of the flesh. We are no different than those who lived in the past. Haven’t you experienced this same thing in your life? You see something in you that you’d like to change and you immediately jump on it with strategies to deny yourself and set up accountability. In years past monks would take vows of silence or severely restrict their activities to combat sin. Today it’s called will power or habit strategies or New Year’s resolutions, but it’s the same approach. And it always fails.
Christians who have been saved through faith in Christ have at their disposal the Spirit who lives inside them. It is this Spirit who gives power to resist and fight and mortify sin.
“And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.” Ezekiel 36:27