Everyone needs to eat. We will get weak, get sick and eventually die if we don’t give nourishment to this physical body.
But Jesus Christ quotes, “Man shall not live by bread alone, but by every word that proceeds out of the mouth of God.”(Matthew 4:4) The design of this body is not only for physical nourishment. It definitely needs nourishment in the spiritual part. Like its physical body, the soul (inner being) will also die if not nourished properly.
In Hebrews 5:12-14, we read that faithfuls who have already received the teachings and had been serving God for quite sometime should have been teachers and what they must receive as spiritual nourishment should be solid food and not milk. In these verses, we can read that there are two kinds of nourishment for the soul. The milk for babies and the solid food for grown-ups.
(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. (13) For everyone who partakes only of milk is unskilled in the word of righteousness, for he is a babe. (14) But solid food belongs to those who are of full age, that is, those who by reason of use have their senses exercised to discern both good and evil.
1 Corinthians 3:1-2, And I, brethren, could not speak to you as to spiritual people but as to carnal, as to babes in Christ. I fed you with milk and not with solid food; for until now you were not able to receive it, and even now you are still not able;
The babies mentioned here are new beings in Christ. Like babies, they will receive milk and the principal teachings or doctrines are considered to be the infant foods for beginners. Meanwhile, those believers who have been serving God for quite sometime, need no baby foods. They must eat solid food like grown-ups do.
Apostle Peter though uses milk as different metaphor from what Apostle Paul use in scolding the believers. In 1 Peter 2:2, he uses milk simply as nourishing food because his emphasis is on desire and not on depth. Paul uses milk as a metaphor for elementary because he wants to give emphasis to the Hebrew people to understand how far they had slipped from their former state of conversion.
Apostle Paul judges the Corinthians as weak based upon their behaviors and attitudes, which reflected no spiritual progress. So he “fed” these immature Christians elementary knowledge because things of greater depth would have gone unappreciated, misunderstood, and unused. And although he hurt the feelings of many in the congregation, he is free and clear before God of any charge of offense. He does not question their conversion, but he certainly rebukes their lack of growth. He rightly judges that they need to have their feelings hurt so they could salvage what remained of their conversion.
An additional insight regarding an insufficient spiritual diet appears in the next chapter. Paul tells them that their problems are directly related to being lazy. Dull in the phrase “dull of hearing” in Hebrews 5:11 is more closely related to “sluggish” or “slothful.” It is translated as such in Hebrews 6:12, “. . . that you do not become sluggish, but imitate those who through faith and patience inherit the promises.”
Paul charges them with being lazy listeners; they are not putting forth the effort to meditate and apply what is taught them. They are, at best, merely accepting. That they are not using what they hear is proof enough for Paul to understand that they are not thinking through the seriousness or the practical applications of the teachings. In other words, they are not assimilating what they hear, and the result is a lack of faith and a consequent faithlessness. His rebuke is far more serious than the one in I Corinthians 3 because these people are older in the faith. They have wasted away a large amount of time that would have been far better spent on spiritual growth.
Paul attempts to shame and shock them into realizing how far they had slipped by calling these grown people—some of them undoubtedly elderly—infants. He goes so far as to tell them that they are unacquainted with and unskilled in the teaching on righteousness. In other words, he attributes to them the one particular trait of infants: that they do not understand the difference between right and wrong, a characteristic that defines immaturity. A parent must instruct and chasten a child until it understands.
The Bible provides ample evidence that a poor spiritual diet results in a spiritually weak and diseased person, just as a poor physical diet works to erode and eventually destroy a person’s physical vitality. Similarly, we can see that a person can be in good spiritual health but lose it through laziness or another form of neglect.
Just as a mature adult needs good, solid nourishment to maintain his vitality and remain free of disease, the spiritual parallel follows. For one to grow to spiritual maturity and vitality, a mature Christian needs solid, spiritual nourishment, assimilated and actively applied, to continue growing and prevent regressing, as opposed to the Hebrews sluggish spiritual deterioration.