Of course all sin should be avoided, but some sins are particularly dangerous. In his classic The Mortification of Sin, John Owen gives six marks or symptoms of sins that will require “extraordinary remedies.” The whole book is simply an extended reflection on Romans 8:13, “If by the Spirit you put to death the deeds of body you will live.” But some deeds of the body don’t die easily. So, what are the marks and symptoms by which we can identify these sins that we should particularly fear?

1. Inveterateness. An inveterate sin is a persistent habit. These lusts may have weathered many a storm and prevailed under the display of a variety of ministries of the Word of God. If this is the case do you think it will prove an easy thing to dislodge such a room-mate, pleading to stay? Old and neglected wounds can prove to be fatal, and are always dangerous. How long has you sin clung so closely (Heb. 12:1)?

2. Secret pleas of the heart for the countenancing of itself. There is a blind optimism that ignores failures and pretends experiences of grace. For a man to gather up his good experiences with God, to call them to mind, to collect them, consider them, and to try to improve them is an excellent thing. To do it, however, to satisfy your conscience when your heart is convicted with sin is a desperate device of the heart that is in love with sin.

3. Frequency of success in sin’s seduction. When the will finds delight in a sin, even though it is not outwardly performed, the temptation is successful. A man may not go along with the sin as to the outward act, yet if he embraces the desire of it in his heart, the temptation has prevailed. If a lust frequently succeeds this way, it is a very bad sign.

4. When a man fights against his sin only because of the consequences or penalty due unto it. A man who only opposes the sin in his heart for fear of shame among men or eternal punishment from God would practice the sin if there were no punishment attending it. On the other hand, those who belong to Christ have the preciousness of communion with God and a deep-rooted hatred of sin as sin to oppose to all the workings of lust in their hearts. Consider Joseph: “How can I do this great wickedness and sin against God?”, my good and gracious God (Gen. 39:9).

5. When it is probable that trouble over a sin is a chastening punishment from God. This one may be harder to discern: how can someone know if there is the chastening hand of God behind his troubled heart? Examine your heart and ways. What was the state of your heart before you fell into the entanglements of the sin now troubling you? Were you negligent in duties or self-discipline? Is there the guilt of any great sin lying upon you that you have not repented of? If any of these are true of you, then you may be like Jonah, fast asleep while the storm of God’s anger surrounds you.

6. When your lust has already withstood particular dealings from God against it. Israel is often described in this condition (Isa. 57:17; 2 Chron. 36:15-16). God had dealt with them about their prevailing lust in several ways, by affliction and desertion; yet they held out against all. This is a sad condition, from which nothing but mere sovereign grace may set a man free, and no one in such a state should presume upon such deliverance.

It looks as if Owen is describing what we might call a habit. A habit is a routine action or thought process that has become so automatic that we often do it without rational premeditation, or sometimes even against rational premeditation. We may say in our heads, “I don’t want to do this. I shouldn’t do this. I will regret doing this.” And yet we proceed. Deeply ingrained habits are powerful, and when they are sinful they must be addressed with great fear and seriousness. They require “extraordinary remedies.”

What Next?
If you identify habits that reflect some or all of the six symptoms above, begin by confessing these sins to God and asking for his help to kill them. Your next step should be to acknowledge these sins to a brother or sister in Christ who is mature enough to help you further diagnose the sin and begin fighting against it to put it to death. Don’t assume you can fight embedded sin patterns alone without help. You can’t. This is why Paul says, “Brothers and sisters, if anyone is caught in any transgression, you who are spiritual should restore him in a spirit of gentleness. Keep watch on yourself, lest you too be tempted” (Galatians 6:2).