Matthew
Matthew 14:6BSB·traditional attribution

On Herod’s birthday, however, the daughter of Herodias danced before them and pleased Herod

John Calvin Reformed @genevareformer

6. And when Herod’s birthday was kept. The Evangelists now begin to relate the stratagem by which Herodias at length succeeded in a design which she had long meditated, the taking away of John’s life. The opportunity was afforded to her by an annual festival, when Herod was celebrating his birthday.

Matthew Henry Presbyterian @wholebiblehenry

We have here the story of John's martyrdom. Observe, I. The occasion of relating this story here, Mat 14:1, Mat 14:2. Here is, 1. The account brought to Herod of the miracles which Christ wrought. Herod the tetrarch or chief governor of Galilee heard of the fame of Jesus.

Commenting on Matthew 14:1-12

John Gill Reformed Baptist @doctorgill

But when Herod's birthday was kept,.... The birthdays of princes, both of their coming into the world, and accession to the throne of government, were kept by the Gentiles; as by the Egyptians, Gen 40:20 and by the (n) Persians, and Romans (o), and other nations, but not by the Jews; who reckon these among the feasts of idolaters.