And immediately the angel of the Lord smote him, because he gave not God the glory: and he was eaten of worms, and gave up the ghost. The angel of the Lord smote him - His death was most evidently a judgment from God.
Because he gave not God the glory - He did not rebuke his flatterers, but permitted them to give him that honor that was due to God alone. See on Acts 12:21 (note).
And was eaten of worms - Whether this was the morbus pedicularis, or whether a violent inflammation of his bowels, terminating in putrefaction, did not actually produce worms, which, for several days, swarmed in his infected entrails, we cannot tell. It is most likely that this latter was the case; and this is at once more agreeable to the letter of the text, and to the circumstances of the case as related by Josephus.
And gave up the ghost - That is, he died of the disorder by which he was then seized, after having lingered, in excruciating torments, for five days, as Josephus has stated. Antiochus Epiphanes and Herod the Great died of the same kind of disease. See the observations at the end of Acts 1:26 (note) relative to the death of Judas.