Summary: Being human we are born with certain default settings that drive us to think in certain ways. When we become a Christian a war starts between a new nature seeking to establish a beachhead and take over and the old regime that wants to stay in control.
The human mind is self-rationalizing. In other words, we will rationalize our thoughts and actions according to ourselves, rather than to some external source. Even when we read something or hear something and alter our behavior, it is because we choose to believe that thing we read or hear—we have rationalized it in our brains. We consider ourselves to be the best resource for determining truth.
This system works fine until we take one thing into consideration: our minds lie to us. In the ancient world, the mind and soul were thought of as the “heart” of a person—the center of their being.
Jeremiah 17:9 The heart is deceitful above all things, and desperately wicked: who can know it KJV
It would be great if the mind was deceitful and good, but such is not the case. In the Garden of Eden, when Adam and Eve decided they knew better than God—that rebellion did something in us. God called it “death” and “sin.” We could no longer see God and we could no longer think clearly. Our DNA was infused with evil passed down through the generations.
The only way out of this mess is for God to “transform” our minds by dealing with our sin by paying for it on the cross then giving us new life by the Spirit of God coming into us to make a permanent abode in our hearts. Now, for the first time, we actually have a choice of how to think. And as we venture further into Chapter 5 of Galatians, Paul points out the choice—go back into legalism and you are thinking in a fleshly, “this age” way. Think like the Spirit and you think like God thinks. We’ll be talking about this for a couple of weeks, but today let’s go through verses 13 through 18.
The main problem in the Galatian churches was the enticement by certain men to go back under the Mosaic Law as a way to “complete” their Christian experience. This is legalism—using an external set of rules or principals to maintain or improve our position with God. Paul has just gotten finished telling the Judaizers to go all the way in their zeal for circumcision as a rite of becoming Jewish and castrate themselves. He’s already called that behavior “a yoke of slavery” (5:1).
In Christ, he says, we have freedom from the law, and freedom from the flesh that is pleased by following the law. You see legalism is very flesh-centric. It makes us feel good to accomplish things, even being good. It’s interesting how Paul clarifies that this freedom from rule and regulation is not just an excuse to behave any way you want. The two greatest threats to a Christian are legalism and the flesh. Using our freedom as a way to indulge that still-present fleshly nature is not what is meant by this freedom. Before Christ you did just what the flesh told you to do, deceiving you all the way. Now, in Christ, you have the freedom to be good because of the Spirit transforming you.
Legalism serves the self. Freedom in Christ allows us to focus, as Jesus does, on one another in addition to ourselves. The Judaizers wanted the Galatians to serve them (4:17) and be enslaved to the Law. The Spirit wants us to be enslaved to Jesus and serve one another in love, not obligation or to earn something.