Sin is a Cancer

It is no surprise that I love the Puritans and a lot of their written works, while dense, they often provide keen insight into the heart of man. Not only that, they have many biblical remedies that they have systematically taken from Scripture and applied to life.

Thomas Watson is one such Puritan. He wrote a book called Repentance, I took the principles and formulated a cheat sheet to better help me and other remember his teachings on this. I hope you find it helpful.


Definition: “Repentance is a grace of God’s Spirit whereby a sinner is inwardly humbled and visibly reformed.”

Chemotherapy for Sin, 6 ingredients to kill the cancer of sin in your life. 

  1. Sight of sin: You must first see your sin before you can repent of it. You have to see it for the cancer that it is, a cancer that will only get worse. Get it diagnosed. 
  1. Sorrow for sin: We must have sorrow for the sin. Inwardly, a deep heartfelt sorrow (Acts 2:37). As the heart is the main actor in sinning so it must be the main actor in sorrowing. This sorrow needs to address it at the root, at the very first evidence even before it blossoms into an action. A true Christian is one who is sorrowful at the heart sin more than just the action. It is also sincere sorrow, sorrow that the sin is against God first and foremost, not sorry just for getting caught. This sorrow isn’t without hope, but it is mixed with faith in the cleansing power of Jesus Christ.
  1. Confession for sin: We must confess our sin rightly and honestly. See next section for Confession. 
  1. Shame for sin: Just as the prodigal son in Luke 15:21 was embarrassed of his actions so also are we to be ashamed of our sin. This shame is a preventative to further sin. “As for you, son of man, describe the temple to the house of Israel, so that they may be ashamed of their iniquities. Let them measure its pattern,” (Ez 43:10)
  1. Hatred for sin: To really eliminate the cancer of sin you must hate that which makes your conscience sick. Christ is never loved till sin is hated. Why embrace the sin that killed your friend Jesus? Why do the sin that Christ had to die for? 
  1. Turning from sin: true repentance is turning away from sin. Just like rust eats away at the iron chain of sin, so does turning away from. Weeping and turning are put together (Joel 2:12) It is a forsaking of sin (Isa 55:7) just like a man forsakes the company of a criminal or abuser. Dying to sin is the life of repentance. It is a heart change, a heart of solid stone turned to flesh, from unfeeling to feeling. It is also a change that is visible to others, a change from darkness to light (Eph 5:8)

All 6 are needed for full effect of remission of this cancer of sin. Just like if you were diagnosed with life threatening cancer, so you must be diligent to take your medicine. Inject your heart with the chemotherapy of repentance. 


Adapted from Thomas Watson, Repentance and Confession

1) Confession must be voluntary

Like the prodigal son in Luke 15:18 who came to himself and realized his own sin; “Father, I have sinned against heaven and in your sight.”

2) Confession must be with great regret

David’s was burdened in confession of his sins: “as a heaven burden they are too heavy for me” (Ps 38:4)

3) Confession must be sincere

Our hearts must be moved with our confession. “I now rejoice, not because you were grieved, but because your grief led to repentance. For you were grieved as God willed, so that you didn’t experience any loss from us. For godly grief produces a repentance that leads to salvation without regret, but worldly grief produces death.” 2 Cor 7:9-10

4) Confession must be specific

See how Israel was specific in their confession of sin. “so they cried out to the Lord, saying, “We have sinned against you. We have abandoned our God and worshiped the Baals.” (Judg. 10.10). The prophet Daniel recites the very sin which brought a curse with it: “We have not listened to your servants the prophets, who spoke in your name to our kings, leaders, fathers, and all the people of the land.” (Dan. 9.6).

5) Confession must be at the root

David acknowledges his birth-sin: “Indeed, I was guilty when I was born; I was sinful when my mother conceived me.” (Psa 51:5). We are ready to charge many of our first sins to Satan’s temptations, but this sin of our nature is entirely from ourselves; we cannot shift it off to Satan. “Be sure there is no root among you bearing poisonous and bitter fruit.” (Deu 29:18).

6) Confession must be against the sin in all its circumstances

Confess sins against knowledge, against grace, against vows, against experiences, against judgments.

7) Confession must take the full blame and not charge God with wrongdoing

“You are righteous concerning all that has happened to us, because you have acted faithfully, while we have acted wickedly.” (Neh 9:33)

8) Confession must be with the resolve not to repeat them

What king will pardon a man who, after he has confessed his treason, practices new treason? Pharaoh confessed he had sinned (Ex 9.27); When Pharaoh saw that the rain, hail, and thunder had ceased, he sinned again and hardened his heart, he and his officials.” (Ex 9:34).


Did anything surprise you about the process of Confession and Repentance?

Where do you struggle the most?

Do you think this is something you could use in your own life?

Published by Matthew.Statler

I joyfully pastor Sierra Vista Baptist Church in Arizona. I'm certified in Biblical Counseling from the Association of Certified Biblical Counselors (ACBC). I graduated from The Southern Baptist Theological Seminary with an MDIV with a concentration in Biblical Counseling. I also am an Iraq war veteran. Matthew Statler SFC, US Army(Ret)

One thought on “Sin is a Cancer

  1. I have heard it said that cancer is not a natural phenomenum. Another shared that cancer are cells rebelling against the existing cells, relating to personal issues the patient has been experiencing. I’ve pondered upon this.

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