Herodias had a grudge against John because he said that, and she wanted to kill him. But she wasn’t able to,
Earlier, Herod had arrested John and tied him up and put him in prison. This was because John had been telling Herod, “It’s against the Law of Moses for you to have Herodias as your wife,” since she’d been the wife of Herod’s brother Philip.
But on Herod’s birthday, the daughter of Herodias danced for Herod and his guests, and she pleased Herod very much.