The writer of Hebrews is about to continue in his discussion of the superior priesthood of Yeshua (Jesus) when he stops and takes a bit of a detour, feeling the need to warn against what he perceives as a serious problem of spiritual immaturity.
Rather than continuing the discussion on the Melchizedekian priesthood, he writes in 5:11 that these Hebrew believers had become “dull of hearing” (the word for dull is translated “sluggish” or “slothful” later on in Hebrews 6:12). One of the first symptoms of spiritual regression, immaturity or backsliding is a dullness toward the Bible. When Bible study seems dull, the preaching at church is boring, and anything spiritual seems uninteresting, the problem is usually not with the teacher or the pastor, but with the believer.
Having been in the faith for quite some time, these believers should have taken on the role of teachers, communicating the truths of the faith, but instead the writer of Hebrews finds himself forced to teach them what he calls the “elementary principles of the oracles of God.” It is as though he is having to teach them the basics of the faith once again.
Part of the problem is that these Jewish believers were being drawn back to the traditional Judaism of their day and the writer of Hebrews felt forced to get back to the basics of the faith before dealing with such a heady subject as Melchizedek. He refers to that teaching as solid food and the more basic teaching of the faith as milk.
In the context of Hebrews, the milk of the Word refers to Jesus’ earthly ministry, His birth, life, teaching, death, burial, and resurrection. The solid food of the Word refers to what He is now doing in heaven as our Great High Priest. We begin the Christian life on the basis of His finished work on earth, personally appropriating His salvation to our hearts and to our lives. We grow in our Christian lives on the basis of His unfinished work in heaven, and adopting the Word of Righteousness.
Of course, even the most mature adult never outgrows milk. As believers, we learn much from our Lord’s work on earth. That, however, should never be enough.
We must make spiritual progress, and we can do this only if we learn about Messiah’s priestly ministry for us in heaven. That is the solid food the writer of Hebrews is talking about. If an adult only eats baby formula (milk) he would be unable to grow and mature since he is not getting the proper nourishment needed. Spiritually, he is unaccustomed, unskilled or inexperienced to the Word of Righteousness. As one grows and matures in his faith, he is supposed to learn to use it in his daily life. Though a spiritual baby lacks information at first, these believers acting like babies have not yet learned to put the Word of Righteousness to effective use in their lives. As James says in James 1:22, they need to be “doers of the word, and not hearers only.”
The result of this maturity is the ability to discern good and evil. Infants do not have the ability to discern. Ultimately the writer’s concern was for his Hebrew readers’ ability to reject the false ideas that confronted and enticed them to leave the faith and return to the Judaism of their day. Had they been sufficiently mature they would be able to discern those ideas as evil against the truths of the faith they should have known were good.