They were cut in sunder. The priests ought to have been thoroughly moved, though they had had hearts of iron, but they burst. [1] Whence we gather that no reasons can prevail with the reprobate, to bring them unto the obedience of Christ; for unless God speak within, the outward doctrine shall be able to do nothing else but to beat the ears. The apostles were able so to overcome their enemies, that they should not have had one word to say; but their fury was so untamed, and unbridled that they do rather go mad. Yet we must therewithal note the force of the word, because although the reprobate are not thereby changed, that they may become better, yet it pierceth into their hearts, so that it urgeth their consciences; for thence springeth their fury, because they saw themselves [2] urged by their judge. They would gladly mock all the gospel, as they attempt whatsoever they can, that they may count it as nothing; but there is in the same a certain hidden majesty, which driveth away mightily all their delicacy. [3] And chiefly when they are cited by the sound of the trumpet to appear before the judgment-seat of God, then appeareth their madness and fury.

Footnotes

1 - "Sed rumpuntur," but they burst (with rage.)

2 - "Se sentiunt," they feel themselves.

3 - "Quae omnes illorum delicias violenter discutit," which, with a strong hand, dispels all their delights.

When they heard that - That which the apostle Peter had said, to wit, that they were guilty of murder; that Jesus was raised up; and that he still lived as the Messiah.
They were cut to the heart - The word used here properly denotes "to cut with a saw"; and as applied to the "mind," it means to be agitated with "rage" and "indignation," as if wrath should seize upon the mind as a saw does upon wood, and tear it violently, or agitate it severely. When used in connection with "the heart," it means that the heart is violently agitated and rent with rage. See Acts 7:54. It is not used elsewhere in the New Testament. The "reasons" why they were thus indignant were doubtless:
(1) Because the apostles had disregarded their command;
(2) Because they charged them with murder;
(3) Because they affirmed the doctrine of the resurrection of Jesus, and thus tended to overthrow the sect of the Sadducees. The effect of the doctrines of the gospel is often to make people enraged.
Took counsel - The word rendered "took counsel" denotes commonly "to will"; then, "to deliberate"; and sometimes "to decree" or "to determine." It doubtless implies here that "their minds "were made up" to do it; but probably the formal decree was not passed to put them to death.

They were cut to the heart - Διεπριοντο, Literally, they were sawn through, from δια through, and πριω, to saw. They were stung to the heart, not with compunction nor remorse, but with spite, malice, and revenge: for, having the murder of Christ thus brought home to their consciences, in the first feelings of their malice and revenge, they thought of destroying the persons who had witnessed their nefarious conduct.

When they heard [that], they (l) were cut [to the heart], and took counsel to slay them.
(l) This shows that they were in a most vehement rage, and tremendously disquieted in mind, for it is a borrowed kind of speech taken from those who are harshly cut in pieces with a saw.

When they heard that,.... This defence of the apostles, in which they still insisted upon it, that they had been the crucifiers of Christ, and yet that he was raised from the dead, and exalted in heaven, and was a spiritual Saviour of men:
they were cut; to the heart, as if they had been cut asunder with a saw; the Ethiopic version renders it, "they were angry", and "gnashed with their teeth", as if a saw was drawn to and fro; they were filled with rage and madness:
and took counsel to slay them; not in a legal and judicial way, but in a private manner, or by force; stirring up the zealots to rise up against them, and dispatch them at once, as blasphemers and heretics.

cut to the heart and took--"were taking."
counsel to slay them--How different this feeling and the effect of it from that "pricking of the heart" which drew from the first converts on the day of Pentecost the cry, "Men and brethren, what shall we do?" (Acts 2:37). The words used in the two places are strikingly different.

Cut to the heart. Convulsed with rage, not sorrow.
Took counsel to slay them. Concerning the expediency of putting them to death.