Nearly 2,000 years ago, the Apostle Paul gave a young minister named Titus some advice that is good for any Christians who long to minister sound Bible doctrine to others:
“In all things shewing thyself a pattern of good works: in doctrine shewing… sincerity” (Titus 2:7).
The dictionary says the word sincere means pure and unmixed. That’s why Paul wrote,
“Let us keep the feast, not with… the leaven of malice and wickedness; but with the unleavened bread of sincerity…” (1 Cor. 5:8).
God told the Jews under the law to keep the “feast” of unleavened bread right after they kept the passover by not mixing leaven in their bread (Lev. 23:4-8), and Paul says that the way to keep that feast today under grace is to keep the leaven of sin out of our lives to show God how thankful we are that “Christ our passover is sacrificed for us” (1 Cor. 5:7).
Now you would think that every believer would know that our lives should be pure and unmixed with sins like “malice” and “wickedness” as we teach the doctrine of grace. But the carnal Corinthians were teaching grace but living in malice (1 Cor. 14:20) and wickedness (1 Cor. 5:13), wrongly believing that grace is a license to sin those particular sins and many others. If that describes your Christian life and ministry of the doctrine of God’s grace, I’d invite you to consider showing sincerity in doctrine instead. Ours is a high and holy calling!
And there are other things with which doctrine shouldn’t be mixed. Paul described his ministry to the Corinthians as one that was conducted “in simplicity and godly sincerity, not with fleshly wisdom” (2 Cor. 1:12). Corinth was a city in Greece, and the Greeks were known for the “wisdom” of their philosophers. So in writing to the Corinthians, Paul decried “the wisdom of men” over and over (1 Cor. 1:17-3:19), insisting that he had not mixed doctrine with worldly wisdom (1 Cor. 2:4) as evidently Corinth’s “ten thousand” false teachers had done among them (1 Cor. 4:15). Perhaps the reason they seem to have bought into this was that they thought such a mixture was the only way to make the doctrine of grace more palatable and popular. That prompted Paul to tell them what he told Titus, that doctrine should be preached in sincerity instead.
Now you’d think that nearly 2,000 years later preachers would know better than to mix Bible doctrine with the wisdom of men. But when the theory of evolution arose, many pastors were intimidated by science–science that was actually nothing more than “science falsely so called” (1 Tim. 6:20). So some of them mixed that example of unbiblical worldly wisdom with the doctrine of creation and came up with something called “theistic evolution.” That’s the theory that claims that evolution is real, but that it was set in motion and superintended by God! And there are many other examples that could be cited of mixing doctrine with the wisdom of men.
But instead of taking your valuable time to cite more examples of the folly of worldly wisdom, I’d rather point out one more thing with which sound Bible doctrine should not be mixed, something Paul pointed out when he told the Philippians about some who “preach Christ even of envy and strife; and… contention, not sincerely” (Phil. 1:15,16). There are believers who mix sound doctrine with things like envy and strife and contention. In other words, they preach doctrine just to pick a fight with others! I hear from men like this all the time, and I believe it is just as dishonoring to the Lord as mixing doctrine with carnal wickedness or fleshly wisdom.
Before you set this article aside, why not pray about this important matter? Doctrine that is unmixed with carnality, human wisdom, or contentious envy and strife is sure to give your words the clarity of sincerity that you long for as you share grace truth with others. source