By what standard? This is one of my favorite questions, and we should ask it more often than we do. This includes those times when the right course of action is disputed among Christians, or when we are honestly confused about what we ought to do. What standard are we using?
On paper, the answer is simple enough. The first answer is that the ultimate standard is the life and example of the Lord Jesus, as recorded for us in Scripture. We are all growing up into the perfect man, the Lord Jesus. He is the standard. The second answer is the law of God contained in the entirety of the Bible. Tota et sola Scriptura. The third answer, at the third level, is where the trouble usually comes, or at least where the overt disagreements appear among Christians. This answer is “wisdom, grounded and steeped in Scripture, and refined through long practice.”
“But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil” (Heb. 5:14). Solid food is for the mature. Immature Christians cannot handle it. What characterizes maturity? Wisdom has experience — “reason of use.” We are told here by implication that some of those who are immature do not have their “sense exercised,” and as a result, what can they not do? They cannot discern good and evil. Now, clearly this does not mean that the immature have no notion of right and wrong. All men know that it is wrong to murder your grandmother for her money. All men know that stealing candy out of little kids’ Halloween buckets is wrong.
But there are areas of life where we don’t all see it the same way. There is a level of ethical discernment which the Bible teaches us is denied to the immature. And of course, additional problems crowd in. There will be legalists who manufacture their own arbitary standards, and when someone protests, all they have to do is say, “you don’t see it because you are still immature. Heb. 5:14.” Yes, this passage will be abused in this way. But the fact that it is abused this way does not remove it from the Scriptures. Libertines abuse forgiveness by grace too, but salvation is still by grace.
Later in Hebrews we are told to consider the outcome of our leaders’ way of life. Where does it all end? Jesus said to judge by fruit. And so all claims to maturity need to be red and full, and weighing the branches down.