Acts 4:1-4

Peter and John Arrested

While they were still preaching, armed men came into the temple area and arrested Peter and John. This group included priests, the captain of the temple and the Sadducees. In a footnote, F. F. Bruce said the captain of the temple, "belonged to one of the chief-priestly families, and in the temple he ranked next to the high priest. The temple guard which he commanded was a picked body of Levites. (It was from this body, presumably, that sentries were detailed to guard the tomb of Jesus, Matthew 27:65 ff.)" Coffman described the Sadducees as

...proud, secular materialists who denied the existence of a spiritual world, holding that neither angels nor demons existed, denying any such thing as the resurrection, and rejecting the OT scriptures, except for parts of them which had political utility, and also refusing the traditions of the elders. Through wealth and political power they had gained control of the religious apparatus which ran the temple, the office of the high priest being regularly filled from this group.

Luke tells us the apostles were arrested because they taught the people and preached the resurrection by preaching about Jesus.

One might well marvel at the fact that the Pharisees, who had so often challenged Jesus while he walked the earth, were not specifically mentioned by Luke as being in the group which took Peter and John prisoner. Perhaps this was because the apostles were teaching the resurrection, in which the Pharisees believed. In fact, Acts often presents the Pharisees as being sympathetic to the church and even obeying the gospel (5:34-40; 15:5; 23:6-9; 26:4-5).

It was now evening, Peter and John apparently having preached for nearly three hours (compare 3:1), so they held them in jail until the next day. If this was to be a criminal case, the Sanhedrin could not try it at night (Walter M. Chandler, The Trial of Jesus, p. 137). Despite their arrest, God caused the preaching of the gospel to bring forth fruit, as Luke reports the number of men who believed came to about 5,000 (Acts 4:1-4). The word "believed" is a synecdoche for full obedience to the gospel.