Paul's inspired illustration about the church is so rich and powerful that Ephesians 5:22-33 is a text that has been used to preach many a sermon about marriage. What the writer of Hebrews does with Divine discipline is just as compelling. In urging the Christians to remain faithful despite persecution (Heb. 12:4), he tells them they had forgotten the biblical exhortation about God's discipline of His children. The writer goes on to use the illustration of earthly parents disciplining their children.
You have seen the fruit of undisciplined children. It is both rotten and smelly, whether it's a toddler's tantrum, an adolescent's attitude, or a teenager's "'tude." Seeing undisciplined children is enough to appreciate the wisdom of statements like "a child left to himself brings shame to his mother" (Prov. 29:15). It is unattractive in youth, but destructive in adulthood.
In Hebrews 12, the writer uses the word "discipline" eight times in seven verses (plus one time inserted by translators in verse 10). That makes it vital to the context of this paragraph. Discipline proves love to children (6), provides legitimacy to children (7-8), produces loyalty from children (9), and perfects pure lives in children (10) though it prompts lamentations in children when it is administered (11). Yet, in showing how He interacts with His faithful ones, God reminds us how He wants us to parent our children. He wants us to teach them discipline.
How do we do that? The writer uses words like "reprove" (5) and "scourges" (6) "as seemed best to them" (10) in a way that "for the moment" is "sorrowful" for the child (11). If you ever had a parent who failed to "spare the rod" of correction, you can relate. We do well to remember that "foolishness is bound up in the heart of a child; The rod of discipline will remove it far from him" (Prov. 22:15).
"Experts" tell us that all corporal punishment will warp and frustrate the recipients. Violent, uncontrolled hitting may well do so, but not loving, measured spankings meant to teach right from wrong. Likewise, having rules and restrictions, consistently enforced, gives a child structure and boundaries. Children actually want to know their limits, and they (and God) expect parents to spell them out to them. Look down the road at the consequences of that kind of parenting. What will your children reap? The inspired writer calls it "the peaceful fruit of righteousness" (11). There are few gifts as precious and meaningful as that!