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. For everyone who partakes only of milk is unskilled in the word of righteousness, for he is a babe. 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. (Hebrews 05:12-14, NKJV).
The apostle Paul writes in his first letter to Timothy, his son in the faith, "[for] bodily exercise profits a little, but godliness is profitable for all things, having promise of the life that now is and of that which is to come." (1 Timothy 4:8, NKJV).
This distinction between bodily and spiritual exercise is repeated here in Hebrews, immediately following the warning about dullness. Like anything in life, maintaining an edge of proficiency, keeping sharp, requires repeated use. Like running or weight-lifting builds up muscle and endurance through repeated use of the physiological systems involved, so too will the continued exercise of spiritual discernment increase our ability to live a godly, Christ-honoring life.
It is a simple formula that works itself out in every other area of human existence, and yet is so prevalently neglected in the realm of faith.
Look, many are very diligent in keeping in physical shape, and this only makes sense as being good stewards of our physical bodies. I am certain most of us in this culture have seen individuals doggedly pursuing their fitness rituals in all kinds of weather conditions, and in whatever other circumstances may be impacting their lives. It is easy to see an almost religious devotion and a willingness to sacrifice in maintaining a rigorous exercise regimen.
Yet many of these same individuals in the world are entirely neglectful of the only realm of living that has eternal significance: obedient faith in Christ, the Savior.
Can you imagine how effective an individual Christian's witness would be if he or she directed the same fierce self-discipline in godly pursuits that someone whose focus was on the world did in their ungodly pursuits?
Can you imagine how much impact to the community a life would be if a person single-mindedly pursued their relationship and knowledge of Christ with the same intensity that many people invest in acquiring things and a good physique?
And this is the essence of the exhortation in the verse above. The writer of Hebrews is soundly criticizing some in his audience who have remained content to be just over the borders of belief, but have not gone beyond into the central regions of the Kingdom.
Instead of being built up in the faith, edified by loving pursuit of God's word and truth, they are content to remain spiritual babes, suckling on the mere milk of the gospel, and not imbibing the solid food of deeper communion with their Creator and Redeemer.
In choosing to remain unfed - and it is a choice along the same lines as any other - these individuals remain unskilled in the word of righteousness. Their ability to discern good and evil remains impaired, polluted and weakened by worldliness and lack of exercise.
There is only one remedy to this condition: immersion in the nourishment of God's word.
This in turn will lead to intensified prayer, fellowship with other saints, and a desire to show ever-growing love by obedience to the One who died to save us, and who lives forever more.
Remember, friendship with the world is enmity with God.
You cannot have it both ways.