What does Matthew 10:15 mean?

Jesus has given detailed instructions to His hand-picked group of twelve men. These are the "apostles," from a Greek term that refers to those "sent out" by a master to carry His message. They will travel from town to town in Galilee, preaching Christ's message that the kingdom of heaven in near, calling all to repent and follow the Messiah (Matthew 10:5–12).

Jesus knew that not everyone who heard the message would believe it. Some would reject the gift of this revelation from God through His Son and His Son's apostles. When that happens, Jesus has told the apostles to shake the dust off their feet on the way out of the house or of the town, if all refuse the truth (Matthew 10:13–14).

Now Jesus declares that this symbolic action taken by the apostles will be a sign of God's coming judgment on that place. Even though they are Israelites, those who reject the Messiah will experience great suffering. Jesus says that the day of judgment will be more unbearable for them than for the land of Sodom and Gomorrah.

Every Israelite would have been familiar with God's dramatic and terrible judgment on the towns of Sodom and Gomorrah in the time of Abraham (Genesis 19). Fire and sulfur rained from the sky and wiped everyone out. Jesus and other New Testament writers often used the judgment they faced as a point of comparison for God's coming judgment on those who reject the gospel of Jesus and the kingdom of heaven. The day of that future judgment is often called the day of the Lord, when Christ returns to earth and the "Son of Man is revealed" (Luke 17:30).

Rejecting Jesus' representatives on this mission would come with a high price. He was trusting them with great responsibility to hold their countrymen accountable for accepting or rejecting the Messiah.