Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do?

Now when they had heard these things, they had compunction in their heart, and said to Peter, and to the rest of the apostles: What shall we do, men and brethren?

And having heard it they were pricked in heart, and said to Peter and the other apostles, What shall we do, brethren?

And having heard, they were pricked to the heart; they say also to Peter, and to the rest of the apostles, 'What shall we do, men, brethren?'

Stung to the heart by these words, they said to Peter and the rest of the Apostles, "Brethren, what are we to do?"

Now when these words came to their ears their hearts were troubled, and they said to Peter and the other Apostles, Brothers, what are we to do?

Now when they had heard these things, they were contrite in heart, and they said to Peter and to the other Apostles: "What should we do, noble brothers?"

When the people heard this, they were conscience-smitten, and said to Peter and the rest of the apostles, "Friends, what can we do?"

They were pricked in heart. Luke doth now declare the fruit of the sermon, to the end we may know that the power of the Holy Ghost was not only showed forth in the diversity of tongues, but also in their hearts which heard. And he noteth a double fruit; first, that they were touched with the feeling of sorrow; and, secondly, that they were obedient to Peter's counsel. This is the beginning of repentance, this is the entrance unto godliness, to be sorry for our sins, and to be wounded with the feeling of our miseries. For so long as men are careless, they cannot take such heed unto doctrine as they ought. And for this cause the word of God is compared to a sword, (Hebrews 4:12,) because it doth mortify our flesh, that we may be offered to God for a sacrifice. But there must be added unto this pricking in heart readiness to obey. Cain and Judas were pricked in heart, but despair did keep them back from submitting themselves unto God, (Genesis 4:13; Matthew 27:3.) For the mind being oppressed with horror, can do nothing else but flee from God. And surely when David affirmeth that a contrite spirit and an humble heart is a sacrifice acceptable to God, he speaketh of voluntary pricking; forasmuch as there is fretting and fuming mixed with the prickings of the wicked. Therefore, we must take a good heart to us, and lift up our mind with this hope of salvation, that we may be ready to addict and give over ourselves unto God, and to follow whatsoever he shall command. We see many oftentimes pricked, who, notwithstanding, do fret and murmur, or else forwardly strive and struggle, and so, consequently, go furiously mad. Yea, this is the cause why they go mad, because they feel such prickings against their will. Those men, therefore, are profitably pricked alone who are willingly sorrowful, and do also seek some remedy at God's hands.

Now when they heard this - When they heard this declaration of Peter, and this proof that Jesus was the Messiah. There was no fanaticism in his discourse; it was cool, close, pungent reasoning. He proved to them the truth of what he was saying, and thus prepared the way for this effect.
They were pricked in their heart - The word translated were "pricked," κατενύγησαν katenugēsan, is not used elsewhere in the New Testament. It properly denotes "to pierce or penetrate with a needle, lancet, or sharp instrument"; and then "to pierce with grief, or acute pain of any kind." It corresponds precisely to our word "compunction." It implies also the idea of sudden as well as acute grief. In this case it means that they were suddenly and deeply affected with anguish and alarm at what Peter had said. The causes of their grief may have been these:
(1) Their sorrow that the Messiah had been put to death by his own countrymen.
(2) their deep sense of guilt in having done this. There would be mingled here a remembrance of ingratitude, and a consciousness that they had been guilty of murder of the most aggravated and horrid kind, that of having killed their own Messiah.
(3) the fear of his wrath. He was still alive; exalted to be theft Lord; and entrusted with all power. They were afraid of his vengeance; they were conscious that they deserved it; and they supposed that they were exposed to it.
(4) what they had done could not be undone. The guilt remained; they could not wash it out. They had imbrued theft hands in the blood of innocence, and the guilt of that oppressed their souls. This expresses the usual feelings which sinners have when they are convicted of sin.
Men and brethren - This was an expression denoting affectionate earnestness. Just before this they mocked the disciples, and charged them with being filled with new wine, Acts 2:13. They now treated them with respect and confidence. The views which sinners have of Christians and Christian ministers are greatly changed when they are under conviction for sin. Before that they may deride and oppose them; then, they are glad to be taught by the obscurest Christian, and even cling to a minister of the gospel as if he could save them by his own power.
What shall we do? - What shall we do to avoid the wrath of this crucified and exalted Messiah? They were apprehensive of his vengeance, and they wished to know how to avoid it. Never was a more important question asked than this. It is the question which all convicted sinners ask. It implies an apprehension of danger, a sense of guilt, and a readiness to "yield the will" to the claims of God. This was the same question asked by Paul Acts 9:6, "Lord, what wilt thou have me to do?" and by the jailor Acts 16:30 "Hecame, trembling,and said, Sirs, what must I do to be saved?" The state of mind in this case - the case of a convicted sinner - consists in:
(1) A deep sense of the evil of the past life; remembrance of a thousand crimes perhaps before forgotten; a pervading and deepening conviction that the heart, and conversation, and life have been evil, and deserve condemnation.
(2) Apprehension about the justice of God; alarm when the mind looks upward to him, or onward to the day of death and judgment.
(3) an earnest wish, amounting sometimes to agony, to be delivered from this sense of condemnation and this apprehension of the future.
(4) a readiness to sacrifice all to the will of God; to surrender the governing purpose of the mind, and to do what he requires. In this state the soul is prepared to receive the offers of eternal life; and when the sinner comes to this, the offers of mercy meet his case, and he yields himself to the Lord Jesus, and finds peace.
In regard to this discourse of Peter, and this remarkable result, we may observe:
(1) That this is the first discourse which was preached after the ascension of Christ, and is a model which the ministers of religion should imitate.
(2) it is a clear and close argument. There is no ranting, no declamation, nothing but truth presented in a clear and striking manner. It abounds with proof of his main point, and supposes that his hearers were rational beings, and capable of being influenced by truth. Ministers have no right to address people as incapable of reason and thought, nor to imagine, because they are speaking on religious subjects, that therefore they are at liberty to speak nonsense.
(3) though these were eminent sinners, and had added to the crime of murdering the Messiah that of deriding the Holy Spirit and the ministers of the gospel, yet Peter reasoned with them coolly, and endeavored to convince them of their guilt. People should be treated as endowed with reason, and as capable of seeing the force and beauty of the great truths of religion.
(4) the arguments of Peter were adapted to produce this effect on their minds, and to impress them deeply with the sense of their guilt. He proved to them that they had been guilty of putting the Messiah to death; that God had raised him up, and that they were now in the midst of the scenes which established one strong proof of the truth of what he was saying. No class of truths could have been so well adapted to make an impression of their guilt as these.
(5) Conviction for sin is a rational process on a sinner's mind. It is the proper state produced by a view of past sins. It is suffering truth to make an appropriate impression; suffering the mind to feel as it ought to feel. The man who is guilty ought to be willing to see and confess it. It is no disgrace to confess an error, or to feel deeply when we know we are guilty. Disgrace consists in a hypocritical desire to conceal crime; in the pride that is unwilling to avow it; in the falsehood which denies it. To feel it and to acknowledge it is the mark of an open and ingenuous mind.
(6) these same truths are adapted still to produce conviction for sin. The sinner's treatment of the Messiah should produce grief and alarm. He did not murder him, but he has rejected him; he did not crown him with thorns, but he has despised him; he did not insult him when hanging on the cross, but he has a thousand times insulted him since; he did not pierce his side with the spear, but he has pierced his heart by rejecting him and contemning his mercy. "For these things he should weep." In the Saviour's resurrection he has also a deep interest. He rose as the pledge that we may rise; and when the sinner looks forward, he should remember that he must meet the ascended Son of God. The Saviour reigns; he lives, Lord of all. The sinner's deeds now are aimed at his throne, and his heart, and his crown. All his crimes are seen by his sovereign, and it is not safe to mock the Son of God on his throne, or to despise him who will soon come to judgment. When the sinner feels these truths he should tremble and cry out, What shall I do?
(7) we see here how the Spirit operates in producing conviction of sin. It is not in an arbitrary manner; it is in accordance with truth, and by the truth. Nor have we a right to expect that he will convict and convert people except as the truth is presented to their minds. They who desire success in the gospel should present clear, striking, and impressive truth, for such only God is accustomed to bless.
(8) we have in the conduct of Peter and the other apostles a striking instance of the power of the gospel. Just before, Peter, trembling and afraid, had denied his Master with an oath; now, in the presence of the murderers of the Son of God, he boldly charged them with their crime, and dared their fury. Just before, all the disciples forsook the Lord Jesus and fled; now, in the presence of his murderers, they lifted their voice and proclaimed their guilt and danger, even in the city where he had been just arraigned and put to death. What could have produced this change but the power of God? And is there not proof here that a religion which produces such changes came from heaven?

When they heard this, they were pricked in their heart - This powerful, intelligent, consecutive, and interesting discourse, supported every where by prophecies and corresponding facts, left them without reply and without excuse; and they plainly saw there was no hope for them, but in the mercy of him whom they had rejected and crucified.
What shall we do? - How shall we escape those judgments which we now see hanging over our heads?

Now when they heard this,.... Or "him", as the Arabic version; that is, Peter speaking these things, describing the character of Jesus of Nazareth; opening the prophecies concerning him; asserting his resurrection from the dead, and exaltation at the right hand of God; ascribing this wonderful affair, of speaking with divers tongues, to his effusion of the Spirit; and charging them home with the iniquity of crucifying him:
they were pricked in their hearts; the word of God entered into them, and was as a sharp sword in them, which cut and laid open their hearts, and the sin and wickedness of them; they saw themselves guilty of the crime laid to their charge, and were filled with remorse of conscience for it; they felt pain at their hearts, and much uneasiness, and were seized with horror and trembling; they were wounded in their spirits, being hewn and cut down by the prophets and apostles of the Lord, and slain by the words of his mouth; they were as dead men in their own apprehension; and indeed, a prick, a cut, or wound in the heart is mortal:
and said unto Peter, and to the rest of the apostles, men and brethren, what shall we do? the persons they before mocked at, they are glad to advise with, what should be done in this their sad and wretched case; what they should do to obtain the favour of God, the forgiveness of their sins, and everlasting salvation. Convinced, awakened sinners, are generally at first upon a covenant of works; are for doing something to atone for their past crimes, to set themselves right in the sight of God, to ingratiate themselves into his favour, and procure the pardon of their sins, and the inheritance of eternal life. And they seem also to be at a loss about the way of salvation, what is to be done to attain it, or how, and by what means it is to be come at; and are almost ready to despair of it, their sin appearing in so dreadful a light, and attended with such aggravating circumstances. Beza's ancient copy reads, "some of them said to Peter", &c. not all that heard, but those that were pricked to the heart.

From the first delivery of that Divine message, it appeared that there was Divine power going with it; and thousands were brought to the obedience of faith. But neither Peter's words, nor the miracle they witnessed, could have produced such effects, had not the Holy Spirit been given. Sinners, when their eyes are opened, cannot but be pricked to the heart for sin, cannot but feel an inward uneasiness. The apostle exhorted them to repent of their sins, and openly to avow their belief in Jesus as the Messiah, by being baptized in his name. Thus professing their faith in Him, they would receive remission of their sins, and partake of the gifts and graces of the Holy Spirit. To separate from wicked people, is the only way to save ourselves from them. Those who repent of their sins, and give up themselves to Jesus Christ, must prove their sincerity by breaking off from the wicked. We must save ourselves from them; which denotes avoiding them with dread and holy fear. By God's grace three thousand persons accepted the gospel invitation. There can be no doubt that the gift of the Holy Ghost, which they all received, and from which no true believer has ever been shut out, was that Spirit of adoption, that converting, guiding, sanctifying grace, which is bestowed upon all the members of the family of our heavenly Father. Repentance and remission of sins are still preached to the chief of sinners, in the Redeemer's name; still the Holy Spirit seals the blessing on the believer's heart; still the encouraging promises are to us and our children; and still the blessings are offered to all that are afar off.

pricked in their hearts--the begun fulfilment of Zac 12:10, whose full accomplishment is reserved for the day when "all Israel shall be saved" (see on Romans 11:26).
what shall we do?--This is that beautiful spirit of genuine compunction and childlike docility, which, discovering its whole past career to have been one frightful mistake, seeks only to be set right for the future, be the change involved and the sacrifices required what they may. So Saul of Tarsus (Acts 9:6).

When they heard this. The conclusion, supported by such convincing demonstration. Before Peter began to speak they did not understand the signs; but now it was clear to them that they had rejected and crucified the Lord.
Pricked in their heart. Convicted of their sins, and pierced with sorrow. They believed Peter's affirmation; their faith revealed their sin in rejecting Christ. Overwhelmed with sorrow, they ask, What shall we do? Is there any way that such sinners can be pardoned?

They said to the apostles, Brethren - They did not style them so before.