The Unholy Trinity: Part Three: The Sinful Nature
June 20, 2004
 
	The past two Sundays we have considered the first two members of the Unholy 
Trinity which wars against our souls. We’ve learned that the devil wars against us with 
his lies, and we’ve learned that the world wars against us by distracting us, leading us to 
conform to its thinking, and even leading us to love the world.
	This Sunday we look at the third member of the Unholy Trinity that wars against 
our souls. I suppose you might argue that this member of the Unholy Trinity is the worst 
of the three. Because while it is to some degree possible to escape the world—at least for 
a time—and while one might even argue that the devil is not always with us, not always 
tempting us, this last enemy is always there, always fighting against us, always with us—
yes, still worse than that, it is always in us.
	This last member of the Unholy Trinity can go by various names—old Adam, 
sinful nature, sinful flesh. And it is a wonderful ally of the devil because while the devil 
is someone outside of us and therefore has to attack from the outside, in our sinful nature 
he has a mole, an operative on the inside, an operative who is rotten to the core, an 
operative who is working non-stop to destroy our souls. The sinful nature is a cancer 
within our own souls, constantly working to eat away at our souls.
	Don’t doubt that you have a sinful nature. If you had two sinful parents, you can 
be sure that you have a sinful nature. As we say in our hymnal’s order of service for Holy 
Baptism, “From our parents we inherit a sinful nature; we are without true fear of God 
and true faith in God and are condemned to eternal death.” (Christian Worship, page 12). 
	That’s not just something that the writers of the hymnal made up, either, because 
Jesus himself said that “Flesh gives birth to flesh.” (John 3:6) and Paul says just how 
deep the corruption of the flesh goes when he writes: “I know that nothing good lives in 
me, that is, in my sinful nature” (Romans 7:18). What does our sinful nature want? Paul 
also writes by command of the Holy Spirit: “For the sinful nature desires what is 
contrary to the Spirit” (Galatians 5:16). In other words, find out what God desires on a 
particular issue, and your sinful nature wants exactly the opposite. God says “Don’t” and 
your sinful nature shouts, “I will.” God says “Do” and your sinful nature says, “I won’t.” 
God says “White” and our sinful nature says “Black.” And if God says  “Black” our 
sinful nature will then say “White.” 
	But don’t understand the sinful nature as merely being disagreeable, as being a 
grumpy old man who means no real harm but is just being disagreeable for the sake of 
having something to do and talk about. No, the Bible says that “The sinful mind is hostile 
to God.” (Romans 8:7) So when God says “Don’t” your sinful nature doesn’t just say “I 
will” but it does so in a decidedly hostile way, prefacing it with some unprintable words 
and a terrifically rude and angry gesture.
	Is that a picture you don’t even want to consider? It is appalling to consider the 
gall and the depravity that it would take to do such a thing? Certainly—but that sort of 
gall and depravity is what is living inside of you right now—that is, living in your sinful 
nature.
	It leads you to be all about—in the words of Paul—“gratifying the cravings of our 
sinful nature and following its desires and thoughts.” (Ephesians 2:3). This attitude, this 
sinful nature shows itself in any number of ways. Paul describes those ways, saying—and 
don’t even try to fool yourself into thinking that this list doesn’t describe your actions, 
your words, and especially your thoughts—“The acts of the sinful nature are obvious: 
sexual immorality, impurity and debauchery; idolatry and witchcraft; hatred, discord, 
jealousy, fits of rage, selfish ambition, dissensions, factions and envy; drunkenness, 
orgies and the like” (Galatians 5:19-21).
	And all these sins make you a slave to sin, a slave to your sinful nature. Jesus 
said, “I tell you the truth, everyone who sins is a slave to sin.” (John 8:34).  Does that 
seem to be going a bit overboard to suggest that someone can really be a slave to sin? 
Ask the addict if it’s going overboard. They know what it’s like to be a slave to sin. But 
don’t merely ask the addict. Ask anyone whose sins have led them to fear for their life 
and to fear for their soul and whose desire to make themselves right before God have led 
them to attempt to be “perfectly clean and sober.” If you don’t believe that your sinful 
nature enslaves you and makes you a sin addict, then either you don’t truly understand 
what sin is or else you’ve never really made an effort to clean yourself up. And cleaning 
yourself up is a hopeless battle because when we are born we are controlled by the sinful 
nature, and Paul assures us that “Those controlled by the sinful nature cannot please 
God.” (Romans 8:8). Therefore the Bible says that “We were by nature objects of God’s 
wrath” (Ephesians 2:3). 
	“We were by nature objects of God’s wrath”. As people who have witnessed at 
many places in the Bible God’s earthly wrath over sin—think of God raining down 
“burning sulfur on Sodom and Gomorrah” (Genesis 19:24) and having the earth open up 
and swallow Korah, Dathan, and Abiram (Numbers 16)—as people who have read these 
examples of God’s earthly wrath over sin, the thought of being an object of God’s 
eternal wrath over sin is a fearsome one. And as people who are all too well aware of the 
power and the total corruption of that sinful nature within us, the threat of being an object 
of God’s eternal wrath is an all too real one. 
	And yet there is the beginning of a hint of hope in that sentence also, isn’t there? 
It’s found in the word “were.” We were objects of God’s wrath—but we are not 
anymore. Our enemy, our sinful nature, made us slaves to sin and objects of God’s wrath 
in the past--but it no longer has that power.
	What happened? Jesus happened—just as God had promised. Jesus was not born 
of two sinful parents, and therefore he did not inherit a sinful nature from them, and 
therefore he was not by nature an object of God’s wrath. Neither did he do anything 
during his life to make himself an object of God’s wrath. Those “acts of the sinful nature” 
that we described earlier, those sins that only increase our guilt before God and make us 
even more deserving of his wrath—Jesus had none of them. And yet—although nothing 
Jesus was or did during his life made him an object of God’s wrath—Jesus was in the end 
an object of God’s wrath. 
	On the cross Jesus was treated as we deserved. On the cross Paul says that “our 
old self was crucified with him” (Romans 6:6). Yes, it was our “infirmities”, our 
“transgressions”, our sinful nature that were paid for on that cross, but it was Jesus 
himself who made the payment, who received the striking, the smiting, the piercing, the 
crushing. (Isaiah 53:4-5).
	That forgiveness is yours, for the Holy Spirit has worked faith in your heart and 
led you to trust that Jesus has destroyed the guilt of your sinful nature. Eternal life is 
yours.
	But don’t let down your guard just yet against your sinful nature. Realize that—as 
God warned Cain—“sin is [still] crouching at your door; it [still] desires to have you” 
(Genesis 4:7). Your sinful nature is still inside of you, still telling you to do what you 
want simply because it’s what you want, to do what you think will feel good simply 
because it will feel good, still telling you to tell God where to get off as you go your own 
way.
	Do not ever stop fighting the battle against your sinful nature. Do not wait for, do 
not expect your sinful nature to change its mind and join your side. It won’t. Do not wait 
for, do not expect your sinful nature to go away. It won’t. Do not wait for, do not expect 
your sinful nature to shrivel up and die. It won’t. 
	Even when your sinful nature is lying there on the floor of your soul, curled up 
into a ball, so weak that it barely has the energy even to whimper, don’t be like those 
people in the movies who deliver a devastating blow to their fierce enemy, sending them 
sprawling to the ground. They often stand around, resting, exulting in their victory, as 
though the battle is over. You know what happens, don’t you? The enemy then has time 
to regain his senses, regain some strength for another attack—an attack that will be all the 
more dangerous because it will come as a surprise.
	If you don’t believe that the sinful nature can do that, if you don’t believe that the 
sinful nature is still powerful in you—yes, even powerful enough to get you to commit 
what are sometimes called “great and shameful” sins—then consider what happened to  
Noah, who carried out a terrific act of faith by building the ark—but then after the flood 
one day drank and drank and then drank some more. (Genesis 9:20-21) Or consider what 
happened to King David, who God called a “man after his own heart.” In faith he took on 
the giant Goliath. In faith he resisted the temptation to strike back at evil King Saul who 
was trying to kill him. When both these enemies were gone, he ruled Israel during its 
golden days. The tough times were over. But sin was crouching at his door in the form of 
sexual temptation. (2 Samuel 11) David opened the door a crack by letting his eyes linger 
on the bathing Bathsheba—and that was all the opening that sin needed to rise up and 
kick the door of David’s soul clear off its hinges. 
	So don’t ever stop fighting the battle. Yes, when your sinful nature has been 
repeatedly beaten by your new self, by the believer, the Christian within you, when the 
sinful nature is lying there on the ground barely able to move, you know what you do? 
You kick him again. Hard. And when he begins to speak—even if it’s just a whisper—
about sin, shut him up immediately and drown him out. Because if you fail to do so, if 
you let the sinful nature talk a bit, if you give the sinful nature a foothold in your mind, it 
won’t be long before you are gradually, perhaps even unknowingly, being captured and 
enslaved by it. It won’t be long before you have wrenched the steering wheel of your soul 
away from the Holy Spirit and handed it over to the sinful nature.
	Oh yes, the sinful nature is going to continue to war against your soul now that 
you are a believer, and it will do so fiercely—even as the devil whispers in your ear that 
there’s really no need to fight that battle since you are a Christian and you can have 
forgiveness any time you want it. Your sinful nature would like nothing better than for 
you to believe that soul-destroying, faith-destroying lie so that it can once again be 
master over you. God warned Cain of just that, saying “It desires to have you.” Then 
God adds, “You must master it.” (Genesis 4:7)
	So how can you keep it from having you? How can you master it? If you want to 
put the sinful nature and its misdeeds to death, do not attempt to use the weak fists of 
human willpower that comes from deep within you. No, remember that the sinful nature 
is what is deep within you. If you attempt to defeat the sinful nature that way, if you look 
within yourself for the power to fight and defeat the sinful nature, you will lose, and you 
will eventually lose everything—your faith, your forgiveness, your salvation.
	If you want to master the sin that is crouching at your door, allow yourself to be 
mastered—not by sin, of course, but the sort of mastery that is described in Romans 8: If 
by the Spirit you put to death the misdeeds of the body, you will live, because those who 
are led by the Spirit of God are sons of God.” (Romans 8:14)  If we are going to 
successfully avoid being once again taken captive, being made a slave to sin, being led by 
sin, then we need to allow ourselves to be led by, to be taken captive by, to be mastered 
by the Spirit.  When we are mastered by the Spirit—and that happens the more that we 
hear, read, learn and take to heart the words that Holy Spirit speaks to us in the Bible—
when we are mastered by the Spirit, we will be able to follow the encouragement of 
Romans 13: “Clothe yourselves with the Lord Jesus Christ, and do not think about how 
to gratify the desires of the sinful nature.” (Romans 13:14) Note that the passage does not 
say, “Do not gratify the desires of the sinful nature” but that it says we ought not even 
think about how to do so. Because once we think about it, our sinful nature has gotten its 
nose in the door—and once it does that, it’s likely to use the leverage to kick the door off 
its hinges. 
	So yes, our fight against the flesh is going to be continual. More than that, it’s 
going to be fierce, it’s going to be ruthless, and it’s going to be brutal. Paul speaks in 
violent terms in Colossians 3 when he tells us to “Put to death, therefore, whatever 
belongs to your earthly nature.” Understand that it’s going to be a battle—an intense, 
brutal war, really.
	So the moment that your sinful nature begins to show even a slight spark of life, 
the moment that it begins to speak—even if it’s just a whisper—the moment it begins to 
tempt you, the moment it begins to lead you to linger on a sinful idea, even though it’s 
going to be painful, even though your sinful nature will scream bloody murder and shout 
that you’re being too extreme, be fierce, ruthless, and brutal. Crucify, put to death your 
sinful nature by getting that thought out of there immediately.
	And the best way to get it out of there is by following Paul’s advice, by replacing 
that thought with something else. That advice is found in Philippians 4, where Paul 
writes: “Finally, brothers, whatever is true, whatever is noble, whatever is lovely, 
whatever is admirable—if anything is excellent or praiseworthy—think about such 
things” (Philippians 4:8). A mind that is filled with such things will have no time or 
space to listen to the sinful nature. In fact, thinking about such things as Paul suggests 
will contribute to a beating down and crucifying of the sinful nature.
	You will find true, noble, lovely, admirable, excellent, and praiseworthy things 
throughout the Bible. Find those things and think about such things. You will especially 
find them in the noble, lovely, admirable, excellent and praiseworthy person of the one 
who called himself “the Truth.” (John 14:6). 
	When you do such things, you will have a mind of the psalmist, who said, “I hate 
every wrong path.” (Psalm 119:104) You will prove the words of the psalmist who said, 
“Those who love the Lord hate evil.” (Psalm 97:10) You will have the mind of Peter, 
who when commanded by God to do something that he believed—albeit falsely--to be 
sinful, responded with a wonderfully strong and violent revulsion, “Surely not, Lord!” 
(Acts 10:14).
	Finally, let us close this sermon series with words of great comfort. The three 
members of the Unholy Trinity—the devil, the world, and our sinful flesh—are indeed 
powerful. But they were no match for Jesus when he was here on earth, and they are still 
no match for him today. Since they are no match for him, then they are no match for 
you—for you are connected with him, grafted as a branch into the vine that is Christ. Out 
battles against these three enemies will be fierce, brutal, and continual. But they are 
battles that you will win through Christ. In Peter’s first epistle he was not expressing 
wishes but promises when he wrote, “[You] through faith are shielded by God's power 
until the coming of the salvation that is ready to be revealed in the last time…The God of 
all grace...will...make you strong, firm, and steadfast. (1 Peter 1:5; 5:10). To that we say 
a hearty, a trusting, and a confident “Amen!”