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. But she could not, for Herod feared John, knowing that he was a righteous and holy man, and he kept him safe. When he heard him, he was greatly perplexed, and yet he heard him gladly.
Mark 6:18-20 ESV