About this we have much to say, and it is hard to explain, since you have become dull of hearing. For though by this time you ought to be teachers, you need someone to teach you again the basic principles of the oracles of God. You need milk, not solid food, for everyone who lives on milk is unskilled in the word of righteousness, since he is a child. But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil. (Heb. 5:11–14)

The author of Hebrews has much he would like to tell the recipients of this letter. There is much knowledge he would like to impart to them, so many important things they need to learn. Unfortunately, what he wishes to communicate is “hard to explain” not because it is obscure or difficult to understand, but because the people have become “dull of hearing.” They are not stupid people and are not intellectually inferior, unable to grasp such truths. The reason he cannot relay these important truths is not because of what these people are by nature, but of what they have become.² There is much the author would like to say, but he cannot and will not because of the spiritual immaturity of the people to whom he writes. They lack understanding, and they lack discernment.

The recipients of the letter to the Hebrews are not new Christians or recent converts, for the author says that by this time they ought to be teachers. This is not to say that they all ought to be ministers or preachers, but that they should all be sufficiently mature so they are able to understand and to teach others the basics of the faith. Sadly, though, they still have not understood the basics themselves.

They do not have the childlike faith Jesus so values but a childish, immature faith. In this way they are like so many Christians since them. Richard Phillips writes:

The recipients of this letter were like many Christians today who think that theology is a waste of time. What difference does it make, people ask, whether God is a Trinity or not, whether Christ’s righteousness comes by imputation or infusion, and whether regeneration comes before faith or after? What is important, they say, is that we get along with each other. Then they cite passages commending a childlike faith, as if that were the same thing as a childish faith, that is, one that is indifferent to or ignorant of the Word of God.³

We live in an age where too many who profess to be Christians rarely consider their spiritual maturity—an age when many consider spiritual immaturity a mark of authenticity, and when people associate doubt with humility and assurance with pride. Far too many people consider sound theology the mark of a person who is argumentative and proud. Far too many people are just like the audience to whom Hebrews is addressed. This letter draws a clear line connecting a lack of discernment with spiritual immaturity so that those who lack discernment are those who are spiritually immature. Scripture makes it plain: if you are not a person who exhibits and exercises discernment you are not a mature Christian.