If you read a sermon—and say you don’t even know who wrote it—and the sermon ministers deeply to you. And then you find out that the person had serious sin in his life, does that nullify the spiritual effect of the truth? And the answer is it shouldn’t if there’s real biblical warrant for that truth.
And maybe the last thing to say in this inadequate answer is the Bible itself encourages us that God uses flawed people, even to write Scripture. I was just blown away recently by re-thinking the life of Moses. The last thing we encounter with Moses is God sternly saying, “You did not believe me at the waters. You struck the rock, you disobeyed me. You didn’t believe me. You will not enter into the promised land.” So here’s a man who’s writing the first five books of the Bible, forbidden from going into the promised land because his disobedience was so serious, God wouldn’t even let him set foot in the promised land.
And then you got Peter who, over there in Galatians 2, is deserting Gentile fellowship, totally out of sync with his own doctrine of justification by faith. And Paul has to get on his case to set him right again. And I love the book of 1 Peter. I love it. It’s true.