Look into the heart and soul of a Christian. You’ll see how God has uniquely equipped the spiritual warrior for a lifelong battle against sin.

A computer. A car. An appliance. Examine an object’s structure and makeup, and you’ll learn what it was made for. What lies inside reveals the thing’s purpose. Lacking the particular equipment, a tool or device can’t perform its stated function.
A person who claims to follow Christ but cannot conquer besetting sins needs to perform a self-evaluation. Without the internal components of saving faith and a new heart, our efforts to avoid evil and pursue good will fail.
According to Thomas Brooks, Satan wants to convince us that faith is unnecessary. You don’t have to trust in the work of Christ to live morally. All that matters is your effort. Keep trying harder and doing better. Faith just complicates things.
For the first time in his book, Brooks opts not to offer remedies against a particular device of Satan. Instead, he reasons with us using proofs from both Scripture and experience.
What we’ll see is that our faith in Christ is absolutely, utterly important as we daily wage war against the vestiges of sin within us. We don’t find the believer’s victory in tools, tricks, and techniques. We find it in the heart God has given us to believe he has already won the battle for us and trust he will help us along the journey home.
Brooks shows us this in six ways.
1. The spiritual warrior’s framework is against sin
Think of the frame of a house. Imagine two identical homes on adjacent lots. From the outside they look equally well built. Yet if you could tear away the brick or siding, the wallboard and insulation, you would see differences in the frames. One house’s frame is made of oak beams, the other of balsa wood.
Which house would you rather live in, in a part of the country that experiences tornadoes? Even a mild storm could pick the second home up from its foundation. But the first home would much more likely weather the storm’s force and remain standing.
This is how the Lord has internally “built” a Christian against sin.
2. The spiritual warrior fights against all sin equally
There are no gradations of sin to the true Christian.
Brooks’ litany of great men of God who each fell to their own deadly sin is sobering. It reminds us that we should never judge a brother or sister in Christ for the sins that beset them. The sin I find repugnant may overwhelmingly tempt another. Yet the sin that so easily drags me down may seem like nothing to that person.
We should also resist the world’s efforts to redefine sin for us. Being on “the right side of history” is meaningless if we’re on the wrong side of God’s will.
This leads us to the third point Brooks makes.
3. The spiritual warrior’s definition of sin comes from God
Brooks explains, in trinitarian categories, that God “argues” for us about the definition of sin. We could rephrase that to say our reasons for calling something sin are God’s reasons. And those reasons come from God’s revealed Word, the Bible.
Scripture doesn’t always point directly at an action or attitude and declare, “There! That is sin.” Jesus didn’t leave us a codified set of rules to follow, as God did with the Israelites through Moses. But there are ways to know certainly that we have transgressed God’s law. This is not an exhaustive list.
Sin is anything that
- Denigrates or mocks the name, the holiness, or the authority of God.
- Denies or rejects the lordship of Jesus Christ or his living, dying, and resurrecting work to redeem the lost
- Attributes the work of the Holy Spirit to Satan (the unpardonable sin Jesus mentions in the gospels)
- Rejects the authority and holiness of God’s revealed Word
- Robs another person of dignity, honor, or worth; or inhibits them from hearing the gospel and responding to it with saving faith
- Calls “good” anything the Bible expressly calls evil, or calls “evil” anything the Bible clearly labels as good
I’m sure we could name more. But the above list covers nearly everything.
4. The spiritual warrior fights sin to the end
Once more, Brooks brings in the Christian’s armor of God. When Paul admonishes the Ephesian church to wield this armor against Satan, he writes: “Put it on. All of it.” He never says we can lay it down. The warrior’s battle doesn’t end until her heart stops beating.
This sounds exhausting. But keep reading.
5. The spiritual warrior fights sin on a level playing field
I confess I had to read this point over and over again until I understood it. Another way to make Brooks’ point is: the believer fights sin with internal harmony. What does this mean, though?
If I know and believe I am saved by grace through faith in Christ Jesus, my conscience is clear. This means I am free of guilt and shame. My sin debt is paid. I am fully reconciled to God. He and He alone is my judge. The result is that I fight from a position of victory. Elsewhere we’ve discussed this as placing the root before the fruit.
Brooks speaks of the internal struggle or dialogue over sin in the Christian soul as being between the same “faculties.” So, if in my conscience I am torn over whether a thing is right or wrong, in Christ my conscience can say, “You know it’s wrong because the Bible calls it sin.” Or, “You are free to choose. The Bible is silent on this issue.”
When I feel weak in my will to resist a temptation, in Christ my will can say, “We have trained for this. You can resist this thing. You are free to obey.”
My heart may long for something God’s Word has forbidden and my affections are torn. But I can then remind myself my affections for Christ are greater – must be greater!
Apart from Christ, a person’s unregenerate conscience becomes judge over his own will. He berates himself, heaping guilt upon an already guilt-laden heart. Or, rejecting God’s Word, he silences his own conscience and forces his will to embrace sin. This internal schism wreaks havoc on the soul.
6. The spiritual warrior fights sin from victory, not for it
The sting of death is sin, and the power of sin is the law. But thanks be to God, who gives us the victory through our Lord Jesus Christ. Therefore, my beloved brothers, be steadfast, immovable, always abounding in the work of the Lord, knowing that in the Lord your labor is not in vain.
(1 Corinthians 15:56–58, ESV)
Note the order in which Paul places these events. Christ has first provided victory to us over sin and death. Because of this, we hold on, press on, and fight on as we daily approach the reward of our efforts.
In our daily, personal campaign against our sinful desires and thoughts, we aren’t so much trudging forward through the thick of warfare. We are soldiers returning home after the end of the decisive battle. Along the way, we engage in one minor skirmish after another. We face “hotspots” of lingering conflict. But we continue moving forward toward our place of rest and celebration.
A final thought
Taken together, we see in these points that faith is the engine of a spiritual warrior. We fight a different battle than the unbeliever because our war exists on different terms. We cannot win without Christ going before us and blazing our trail through enemy territory. Having Christ, we make our way home, remaining spiritually armed until the end.
I agree