Hebrews 5:12

12 In fact, though by this time you ought to be teachers, you need someone to teach you the elementary truths of God’s word all over again. You need milk, not solid food!

Read Hebrews 5:12 Using Other Translations

For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat.
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,
You have been believers so long now that you ought to be teaching others. Instead, you need someone to teach you again the basic things about God’s word. You are like babies who need milk and cannot eat solid food.