Mark 6:18 Meaning: The Law and the Prophet's Cost
For John had said to Herod, “It is not lawful for you to have your brother’s wife.”
For John had said unto Herod, It is not lawful for thee to have thy brother’s wife.
For John said unto Herod, It is not lawful for thee to have thy brother’s wife.
for John said to Herod--`It is not lawful to thee to have the wife of thy brother;'
For John said to Herod, It is not lawful for thee to have the wife of thy brother.
Meaning in one sentence
Why John said Herod's marriage was unlawful, and what his boldness teaches about speaking truth.
Context
The story in Mark 6 takes us into the court of Herod Antipas, the ruler of Galilee. Herod had married Herodias, the wife of his own brother Philip. This marriage violated the law given in Leviticus, which forbade a man from taking his brother's wife while the brother was still alive. John the Baptist, the prophet preparing the way for Jesus, did not stay silent. He confronted Herod directly, repeatedly telling him that what he had done was not lawful. This bold word cost John his freedom and eventually his life. Mark explains this background to show why John was arrested and beheaded, and to reveal the cost of prophetic faithfulness.
Key Words
The Greek verb behind "had said" is elegen, in the imperfect tense. That tense matters: it means John did not tell Herod once and stop. He kept saying it, probably every time he had an audience with the king. John was persistent, not because he enjoyed conflict, but because the truth mattered. The word for "lawful" is exestin, meaning something is permitted or right under God's law. John was not appealing to Roman law or custom. He was pointing to the clear command in Leviticus: a man shall not take his brother's wife. The word for "brother" is adelphos, which simply means a male sibling. Philip was Herod's full brother. So John's case was not about a technicality. It was about a plain violation of God's order. He spoke the law plainly, and he did not stop speaking it.
How Christians Read This Verse
Christians across traditions have seen in this verse a picture of prophetic courage. Protestant commentators like Barnes note how Herod feared John yet would not repent. Anglican scholars point out the historical background of Herod's marriage violating Jewish law. Reformed readers through the Geneva Bible highlight John's faithfulness in confronting sin directly. Catholics and Orthodox who honor John as the Forerunner see his boldness as essential to his mission of preparing hearts for Christ. All agree: John spoke not from personal anger but from God's clear command, and his words led to his death. The different traditions simply emphasize different aspects of the story, but they all hold up John as a model of truth-telling.
A common misunderstanding
Some think John was meddling in Herod's private life. But the law of God was clear, and as a prophet John was required to speak it. The cross-references in Leviticus show that such a marriage was forbidden. John was not being personal; he was being faithful. He gave the king a chance to repent, which makes Herod's refusal all the more tragic.
Living This Out
This verse asks you to consider what truth you are avoiding. Herod heard John gladly but would not change. He listened, admired, and did the opposite. Most of us are not kings, but we all have something we do not want to hear. Maybe it is about a relationship, a habit, or a pattern of sin. John's words remind us that God's law is not a suggestion. It is a boundary for our good. This week, you could ask: Is there a 'John' in my life telling me something I need to hear? Or is there a truth I need to speak to someone else? Honesty is costly, but silence is more costly.
Main takeaway: John's bold word to Herod shows that speaking God's truth faithfully is worth any cost.
For Families
For ages 5, 8
John loved God and told the truth even to a king. The king was doing something wrong, and John said so. It made the king angry, but John was right.
For ages 9, 12
John the Baptist was not afraid to tell Herod that his marriage was against God's law. Even though it cost him his freedom and eventually his life, John did not stop speaking the truth. This shows us that loving God means obeying Him and telling the truth, even when it is hard. It also reminds us to listen when someone tells us something we don't want to hear, because it might be God speaking through them.
Questions People Ask
Why was it not lawful for Herod to have his brother's wife?
Under the law of Moses (Leviticus 18:16; 20:21), a man was forbidden to marry his brother's wife while the brother was still alive. Herod had taken Herodias from his brother Philip, who was still living. So John correctly pointed out that this marriage violated God's law.
Did John speak this to Herod just once?
The Greek verb elegen ('had said') is in the imperfect tense, which suggests John said this repeatedly. He did not confront Herod once and stop; he kept warning him, probably every time he had the opportunity.
Was John meddling in politics?
John was a prophet. Prophets in the Old Testament often confronted kings about their sins. John was not interfering in politics for its own sake; he was calling Herod to repent. The law was clear, and John was faithful to speak it.
Why did Herod listen to John if he didn't obey?
Mark 6:20 says Herod feared John, knowing he was righteous and holy. He liked listening to John and did many things he said, but he would not give up Herodias. He tried to compromise with his conscience.
How does this verse connect to John's death?
John's words made Herodias furious. She wanted John dead. Though Herod hesitated, she eventually manipulated Herod into beheading John (Mark 6:21-28). John's boldness directly led to his martyrdom.
For pastors & researchers
Greek interlinear, 8 commentaries & word study