The author’s concern is with the apparent slowness of his audience to catch on, describing them as children who need milk instead of meat, “…for everyone who lives on milk is unskilled in the word of righteousness, since he is a child” (5:13). The challenge is to “…leave the elementary doctrine of Christ and go on to maturity…” (6:1) marked by an ability to wrestle with good and evil and choose the good.
It is in the application of truth that we discover just how much of what we have come to believe is actually rooted in our hearts and not just recorded in our minds. Discernment, the ability to distinguish good from evil, may be a spiritual gift (1 Corinthians 12:10) but it is also a natural response that needs to be developed in every believer. The writer to the Hebrews insists that here, “practice makes perfect.”
Truth must be applied if we expect to grow in our spiritual lives. I was struck by this yesterday in Sunday School. Some of the children exhibited just what immaturity in the faith looks like. They knew the correct answers but immediately resisted or refused to apply those answers in real-life situations. For example, they knew that being helpful was good (and parroted back what they had been told previously) but resisted being helpful by picking up their garbage and depositing it in the garbage can.
But there is another critically important issue here. I could force (and I did) those children to pick up their garbage. But did they do so because they distinguished the difference between good and bad and chose to do the good? Doubtful. We can manipulate, or intimidate others, into doing what they should do but that’s not spiritual growth.
Unless their hearts are engaged, their behaviour can only be manipulated, not forever altered. That is why the first great commandment given to us by Jesus is to love God with all our heart, with all our soul, with all of our mind and with all of our strength and THEN love our neighbour (Mark12:30, 31). The second is not consistently or honestly possible without the first.
The principle applies to developing discernment, to being able to distinguish right from wrong and then choosing to do the right. The more our love relationship with God grows, through faith in Christ, through exposure to His Word, through prayer and the ministry of the Holy Spirit in our lives, the greater will be our ability to make choices that bring glory to Him. That’s spiritual maturity.