Charles Ellicott Commentary Acts 5:21

"And when they heard [this], they entered into the temple about daybreak, and taught. But the high priest came, and they that were with him, and called the council together, and all the senate of the children of Israel, and sent to the prison-house to have them brought." — Acts 5:21 (ASV)

Early in the morning.—Probably at daybreak, when the worshippers would be going up to the Temple for their early devotions, or, though less probable, at the third hour, the time of the morning sacrifice.

Those who were with him.—Probably those named in Acts 4:6, who seem to have acted as a kind of cabinet or committee.

All the senate...—Literally, the word means, like "senate," the assembly of old men, or elders.

They are here distinguished from the Sanhedrin, which itself included elders in the official sense of the word. They were also probably a body of assessors—how chosen we do not know—specially qualified by age and experience, and called in on special occasions. They may have been identical with the whole estate of the elders of Acts 22:5.