Deep in human hearts is an engine of self-justification. We all desperately want to reassure ourselves that we are all right. We do this by destroying anything that reminds us of the absolute standards of God’s righteousness. Anything that points out our sin and need for God makes us nervous, guilty, resentful. Since Jesus was the perfect teacher and embodiment of God, he was hated the most. But if we are like him in any degree, we will get rejection too. Real godliness is off-putting and intimidating and maybe even infuriating or awesome and amazing - but never simply pleasant. (Tim Keller, Mark: Redeemer Bible Studies, p. 65).

For John had been saying to Herod, "It is not lawful for you to have your brother's wife."  And Herodias had a grudge against him and wanted to put him to death...(Mark 6:19)

And [Salome] went out and said to her mother, "for what should I ask?"  And [Herodias] said, "The head of John the Baptist." (Mark 6:24)