Acts 12:1

A comparison of the last verses of Acts 11 and this chapter (Acts 12) suggests that Barnabas and Paul made that trip to Jerusalem with relief for the victims of the famine at about the time of the events given in Acts 12, this being in 44 A.D., a date determined by the death of Herod Agrippa I. That monarch had succeeded in putting together the whole domain of his grandfather Herod the Great, and had also been given the title of king by Claudius. He was a staunch friend of the Jews and was no doubt influenced by them to make the move to destroy Christianity.

He martyred James, seized and imprisoned Peter, planning to execute him publicly after the Passover festivities. Nowhere in the New Testament does the intervention of Almighty God on behalf of his church appear any more timely and dramatic than in this chapter. With their friend on the throne, the Jewish hierarchy decided to exterminate Christianity; and there was no reason why they could not have succeeded, except for the intervention of the Father in heaven.

When the earthly fortunes of the Christians seemed the most precarious, however, providential events took place with sudden finality, lifting the threat completely. At the precise instant when one apostle was already dead, another imprisoned and condemned, and the entire Twelve proscribed by an all-powerful ruler acting as a Jewish deputy in the whole procedure, out of a desire to please his subjects, at that very moment God sent an angel to release Peter and shortly thereafter struck Agrippa dead. The same event doomed secular Israel.

The Encyclopedia Britannica has this regarding Herod's death:

His sudden death in 44 A.D. ... at Caesarea during games in honor of Claudius was a disaster for Jewry, because with all his faults of sycophancy and ostentation he had successfully kept the balance between Rome and the Jews and shown that the two could co-exist to the advantage of both.[1]

It is ironic that the Jews who had, in the elevation of Herod Agrippa I, achieved for themselves tolerance and accommodation, should at the same time have refused so adamantly to extend the same to Christians; and that God's thwarting of their campaign against the body of Christ, by the summary execution of Herod, also by that same event removed the one man who could have preserved their own toleration by Rome. The final result of what took place when God sent an angel to destroy Herod Agrippa was realized some 20 years later when Titus and Vespasian destroyed Jerusalem. The finger of God is clearly seen in this chapter.