Matthew Poole and continuators on Acts 12:3

3 And because he saw it pleased the Jews, he proceeded further, to take Peter also. Then were the days of unleavened bread.

All the posterity of Herod the great, by his example studied chiefly to please the Roman Emperors, and to gratifie the Iews whether by right or wrong.

Or the Passover, which Festival-solemnity lasted eight days; and God over-ruled the hypocrisie of Herod, (for he did not out of piety observe this time) for the preservation of Peter; and Herod might fear some tumult of the people, in so great a concourse, upon Peters death, for which he did defer it; howsoever, the perverseness of the Iews is very remarkable, who were made with rage against Christ and his Apostles, at such times in which they pretended to serve the God of love and peace.

Marginal references: Exod. 23.15.