The phrase “spare the rod, spoil the child” comes from Proverbs 13:24, “He who spares the rod hates his son, but he who loves him is careful to discipline him.” The Lord uses discipline to reveal our sin to us. This is also how parents reveal the truth of our need for a Savior to their children. When a child does not feel the consequence of his sin, he will not understand that sin requires punishment. The Lord provides a way to salvation and forgiveness through Jesus, but that means little to those who do not see their sin.
Furthermore, correction shows us that we are not above reproach and that we are accountable for our actions. Our natural pride blinds us to our need for a Savior, and discipline reveals the truth of our wretchedness (Revelation 3:17). Since salvation is the most important choice the child will ever make, it is imperative that parents are leading them to Christ, and discipline is critical to this process. Proverbs 23:13 says, “Do not withhold discipline from a child; if you punish him with the rod, he will not die.” In the context of verse 13–14, “die” means spiritual death of hell. Children who respect authority and feel sorrow for their sin are much more likely to ask Jesus to forgive them and be saved.
All children are born sinful (Romans 5:12–19). Their natural self is destructive and unrighteous. That does not mean they aren’t infinitely valuable and worthy of love (Psalm 127:3). It means that they are not born with any natural “goodness” in them. That is why all children need discipline. Proverbs 22:15 says “Folly is bound up in the heart of a child, but the rod of discipline will drive it far from him.” Discipline is critical for wisdom (Proverbs 29:15), and a child who obeys his parents will be wise (Proverbs 13:1). And even adults who do not heed correction will feel the consequences of their foolishness (Proverbs 10:13).
Some people believe in discipline, but not in physical discipline such as spanking. However, the Bible is the final word on what is truth; it is not mere opinion or theory. The word “rod” indicates a thin stick or switch that can be used to give a small amount of physical pain with no lasting physical injury. A child should never be bruised, injured, or cut by a physical correction. The Bible warns that parents should never abuse the power and authority they have over their children while they are young because it provokes the children to righteous anger (Ephesians 6:4; Colossians 3:21). Physical discipline is always done in love, never as a vent to the parent’s frustration. It is also just one part of discipline and should be used when the child shows defiance to a clear limit, not in the heat of the moment.
God instructs parents to parent their children the way He parents His children. Hebrews 12:5–11 tells us that God disciplines those whom He loves to perfect their righteousness. God only disciplines His own, which proves that Christians are His beloved children. Notice that David says that the Lord’s rod comforts him in his time of trouble (Psalm 23:4).
Finally, we know that no discipline feels good while it is happening, but afterwards the rewards are rich (Hebrews 12:11). Godly character, fruit of the spirit, and peace are rewards of God’s discipline. The same is true for our human children. Children who have learned how to take responsibility for their actions are much happier people (Proverbs 3:11–18). The importance of the rod of correction is that it steers the heart of a child toward Jesus and forgiveness of sin He offers. When parents trust God’s methods over their own, they will see the blessings for their children and themselves.
 Got Questions Ministries. (2010). Got Questions? Bible Questions Answered. Bellingham, WA: Logos Bible Software.