In chapter 4 it speaks of John being arrested, why was he?
Matthew 14 gives us a little bit of the backstory. It seems John knew how to make a ruler angry. Herod had married his brother’s wife, which wasn’t right for him to do, John had called him out on it.
Matthew 14:3-5
“Now Herod had arrested John and bound him and put him in prison because of Herodias, his brother Philip’s wife, for John had been saying to him: “It is not lawful for you to have her.” Herod wanted to kill John, but he was afraid of the people, because they considered him a prophet.”