A.T. Robertson Commentary Acts 12:3

"And when he saw that it pleased the Jews, he proceeded to seize Peter also. And [those] were the days of unleavened bread." — Acts 12:3 (ASV)

That it pleased the Jews (οτ αρεστον εστιν τοις Ιουδαιοις). Indirect assertion with the present tense εστιν retained. Αρεστον is the verbal adjective from αρεσκω followed by the dative as in Joh 8:29.

Proceeded to seize (προσεθετο συλλαβειν). A patent Hebraism in Lu 20:11f. already, and nowhere else in the N.T. It occurs in the LXX (Genesis 4:2; Genesis 8:12; 18:29, etc.). Second aorist middle indicative of προστιθημ and the second aorist active infinitive of συλλαμβανω. Literally, he added to seize, he seized Peter in addition to James.

The days of unleavened bread (ημερα των αζυμων). By this parenthesis Luke locates the time of the year when Peter was arrested, the passover. It was a fine occasion for Agrippa to increase his favour among the crowds of Jews there by extra zeal against the Christians. It is possible that Luke obtained his information about this incident from John Mark for at his Mother's house the disciples gathered (12:12).