In Matthew 18:6, Jesus issues a stern warning to those who cause others to sin: “If anyone causes one of these little ones—those who believe in me—to stumble, it would be better for them to have a large millstone hung around their neck and to be drowned in the depths of the sea” (see also Mark 9:42 and Luke 17:1–2). The “little ones” are true disciples of Jesus, whether young or old, who are identified by their childlike trust in God. This interpretation is substantiated by the immediate and wider context of the Gospel of Matthew.
Matthew 18 begins with the disciples asking, “Who, then, is the greatest in the kingdom of heaven?” (Matthew 18:1). After placing a child among them (verse 2), Jesus answers, “Truly I tell you, unless you change and become like little children, you will never enter the kingdom of heaven. Therefore, whoever takes the lowly position of this child is the greatest in the kingdom of heaven. And whoever welcomes one such child in my name welcomes me” (verses 3–4). Jesus used the child as a visual aid to illustrate His point about humility and faith. So, the text is not necessarily about children, although it could be. Instead, it is about becoming like children and entering the kingdom of heaven. It is about being a true disciple of Jesus.
The wider context also substantiates this interpretation. In Matthew 10:42, Jesus says, “If anyone gives even a cup of cold water to one of these little ones who is my disciple, truly I tell you, that person will certainly not lose their reward.” True disciples show kindness and hospitality to one another (cf. Galatians 6:10), even in small ways such as offering a cup of cold water. This act of kindness may seem insignificant, but Jesus promises that it will not go unnoticed or unrewarded.
Just as there are positive rewards for whoever shows kindness and hospitality to other disciples, there are also grave consequences for whoever causes one of these little ones—those who believe in Christ—to stumble. The punishment is severe and graphic. Jesus says that it would be better for that person to have a large millstone hung around his neck and to be drowned in the depths of the sea.
A millstone is a large, heavy, circular stone that was used in ancient times to grind grain into flour. The milling process used two stones: a bed stone and a runner stone. The bed (or base) stone remained stationary, while the runner (or top) stone was turned by an animal, such as an ox or donkey, walking in a circle around the lower stone.
The image of someone sinking to the bottom of the sea with a millstone around his neck is a call to take this warning seriously. If we lead others astray and cause them to sin, we do great harm to them and to ourselves. Jesus promises that such an offense will not go unnoticed or unpunished. In fact, the punishment would be so terrible that it would be better to drown in the sea than to face it.
As Christians, we should be mindful of how our actions impact others, especially those who are in the household of God. It is our responsibility to be a positive influence in their lives, helping them to grow spiritually and avoid anything that could cause them to sin. If we do cause others to sin, we should confess our wrongdoing and seek forgiveness, both from God and the ones we wronged. In doing so, we demonstrate that we are true disciples of Jesus (John 13:35).