12 For though by this time you ought to be teachers, you need someone to teach you again the first principles of the oracles of God; and you have come to need milk and not solid food.
Verses 12 and 13 show the result of spiritual dullness.
The word “for” explains why the readers of Hebrews were “slow to learn.” There is a contrast between what they were (immature) and what they should be (mature).
though by this time you ought [need] to be teachers,
Since the readers of Hebrews had been Christians for some time, they should have reached the point where they could teach others. Mature ought to teach the immature. Their responsibility as mature believers was to help others grow into spiritual adulthood.
you need someone to teach you again the first principles
The “first principles” are basic, rudimentary, or elementary truths of the Bible. In this case these principles have to do with New Testament truths such as the doctrine of the church, especially the doctrine of Christ Himself (He 6:1-2).
The readers of Hebrews needed to go back to the basics of their faith. They were in the mistaken process of relapsing back into the Old Testament economy. They were not even at the point of knowing their ABCs yet. Their desire to go back to Old Testament types when the Antitype had come demonstrated their ignorance of the New Testament economy.
of the oracles of God;
“Oracles” refer to divine utterances. The readers of Hebrews needed to go back to the rudimentary teachings of New Testament truth.
and you have come to need milk
Their insolence against understanding the supremacy of Christ put them in the place of baby Christians. The milk metaphor indicates a basic craving for food rather than a more complex craving. They could not assimilate solid food but only milk or liquid food. They needed to go back to the basics of Christianity to correct their failure to understand the difference between the type of the Old Testament and the Antitype of the New Testament.
and not solid food.
The baby Christians of Hebrews had not grown to the point where they could imbibe solid food; they were still on their mother’s breast spiritually speaking. Solid spiritual food is necessary to grow in faith.
Immature Christians tolerate only the liquid diet of basic teaching.
Christians who waver from the fundamentals of what they believe do not have stability in their faith. It is especially egregious when people who have been Christians a long time submit to distorted teaching. Time alone does not produce spiritual maturity.