As they were speaking to the people, the priests and the captain of the temple guard and the Sadducees came up to them, being greatly disturbed because they were teaching the people and proclaiming in Jesus the resurrection from the dead. And they laid hands on them and put them in jail until the next day, for it was already evening. But many of those who had heard the message believed; and the number of the men came to be about five thousand. On the next day, their rulers and elders and scribes were gathered together in Jerusalem; and Annas the high priest was there, and Caiaphas and John and Alexander, and all who were of high-priestly descent. When they had placed them in the center, they began to inquire, “By what power, or in what name, have you done this?” Then Peter, filled with the Holy Spirit, said to them, “Rulers and elders of the people, if we are on trial today for a benefit done to a sick man, as to how this man has been made well, let it be known to all of you and to all the people of Israel, that by the name of Jesus Christ the Nazarene, whom you crucified, whom God raised from the dead—by this name this man stands here before you in good health. He is the STONE WHICH WAS REJECTED by you, THE BUILDERS, but WHICH BECAME THE CHIEF CORNER stone. And there is salvation in no one else; for there is no other name under heaven that has been given among men by which we must be saved.”
captain of the temple guard - an official second only to the high priest; he was responsible for order in the Temple
Sadducees - They hated the idea of resurrection that the apostles were preaching (Matt 22:23).
"The origin of the name is rather to be sought in the fact that they were descendants of Zadok, the famous high priest of the days of David and Solomon (2 Sam 8:17; 1 Kings 2:35), though some refer them to another and little known Zakok, a disciple of Antigonus of Socho. We know that the posterity of the great Zadok held the office of high priest down to the era of the Exile, as also that the main body of the post-exilic priests were sons of Zadok. Cf. also Ezek. 40:46; 43:19;48:11. The chief priests down to the close of the Greek period are known to have been drawn from their ranks; and, under the Romans, the Sadducees both held the high-priesthood and had also a distinct preponderance in the Sanhedrin. Thus, though forming only a small minority of the Jews, they were a sort of priestly aristocracy, possessing great political influence. They were not nearly so popular as the Pharisees or strictly religious party. The Sadducees cared chiefly for the maintenance of the State, and were largely indifferent to religion except in so far as it was a matter of custom and expediency. They play a conspicuous part, as we shall see, in the history of the Acts, because the progress of the Gospel threatened their influence and interests.
As to doctrines, they held, in opposition to the Pharisees, (a) that only the written Law was binding, and not the oral traditions of the elders; (b) that there is no resurrection of the body, or system of future rewards and punishments; (c) that the existence of angels and spirits, i.e., of a supermundane world, is a myth; (d) that man is master of his own destiny, and that his own free will must guide him, without any supposed influence of divine predestination and grace." (Walker)
"But there is greater significance to this Sadducean hostility to Christ. It had been the Pharisees who had led the opposition to Christ before His death and resurrection. Now the Sadducees had taken the lead. The reason is clear when we take into account the beliefs of these two sects. From Matthew 22:23 we learn that 'the Sadducees ... say that there is no resurrection,' while in Acts 23:8 we find their teaching as to this contrasted to that of the Pharisees; 'For the Sadducees say that there is no resurrection, neither angel, nor Spirit: but the Pharisees confess both.' Necessarily, therefore, the multiplied testimonies to the resurrection of Christ were embarrassing the Sadducees even more than the Pharisees." (Stam)
v 4 - "In Chapter 4 of the Book of Acts we begin to find the answer to the apostles' question: 'Lord wilt Thou at this time restore again the kingdom to Israel?' (Acts 1:6). As we have observed, our Lord did not tell His apostles whether or not the kingdom would be restored at that time because, humanly speaking, that depended upon the answer to another question: Would Israel now accept Christ? In the records of our Lord's earthly ministry it is stated again and again that many of the Jews believed on Christ. In the Book of Acts it is the same. The chapter on Pentecost records the turning of three thousand to Christ, while Chapter 4 opens with the number brought up to five thousand men. But this by no means implies the conversion of Israel as a nation at that time, nor did these individual conversions warrant the restoration of the Davidic Kingdom, for these thousands of Messiahs followers in Israel still constituted only a small minority in the nation and they did not represent Israel's government. The primary question in early Acts, then, is: What will the nation Israel, her government, her rulers, do about Christ?" (Stam)
ruler and elders and scribes - "The word 'Sanhedrin' means 'Council' and stands for the ruling Body and supreme authority among the Jews. We do not know when this Council first came into existence, though the Jews themselves trace it origin back to the 'seventy elders' whom appointed (Num 11:16-30). In allusion to that event, it consisted of seventy members, with a president, making seventy-one in all. It was in active existence in the Greek period, and, under the Romans, was still allowed to exercise authority, with certain important limitations. It was accustomed to assemble in the precincts of the temple, in a hall called 'the Hall of Hewn Stone', the members being seated in a semi-circle, with the president in the centre." (Walker)
Annas - "Annas the high priest; Cf. Luke 3:2; John 18:13, 24. He had been appointed high priest by the Roman legate Quirinus (Cyrenus) in A.D. 6 or 7, but deposed by the procurator Valerius Gratus in A.D. 14-15, so that he was not actually high priest at this time. But, though he had lost his former office, he still retained great influence and power, as is shown by the fact that our Lord was first taken to him for examination (John 18:13). We learn from Josephus that he had five sons, all of whom attained to the high priestly office. Caiaphas, also, who was now high priest, was his own son-in-law. The old title still clung to Annas, and it may be that he was encouraged to ignore his deposition. Perhaps, too, he was Nazi or president of the Sanhedrin, and some have advanced evidence tending to shew that there was a deputy-high-priest, who acted as locum-tenens for the high priest proper in case of need. But, apart from such conjectures, we have precedents in Josephus for employing the term 'high priest' of one who had formerly held that office. Annas belonged to the Sadducean party, and was virtually its chief, being very rich and influential. Precedence is given him in this verse, as he clearly overshadowed his son-in-law. Josephus calls him 'Ananus'. It must not be forgotten, also, that the word translated 'high priest' (ἀρχιερεύς) occurs frequently in the New Testament in the plural, being rendered 'chief priests' in our version. It is thus translated both 'high priest' and chief priest'. As head of the body of 'chief priests', Annas had, beyond all doubt, a unique position. Matt. 26:3, 57; Luke 3:2; John 11:49; 18:13, 14, 24, 28." (Walker)
Caiaphas - "His full name was Joseph Caiaphas, and he was appointed high priest in A.D. 18 by Valerius Gratus who preceded Pontius Pilate as procurator of Judaea. His pontificate lasted till A.D. 17, when he was removed from office by Vitellius. He is notable both for his dictum that it was expedient that one man should die for the people and also for the fact that he was the high priest at whose tribunal our Lord was condemned. As mentioned above, he was son-in-law to Annas." (Walker)
"Calaphas was the ruling high priest (AD 18-36), though Annas (high priest AD 6-15) continued to exercise weighty influence (cf Lk 3:2; Jn 18:18)" (Ryrie)
John ... Alexander - we know nothing about these men
"In the next place Peter quotes the Word of God. The Holy Spirit puts the same Scripture before these rules, elders and the chief priests, which the Lord had mentioned in their presence. 'By what authority doest thou these things?' the same men had asked Him, who now asked His disciples. And the Lord had answer them in parable (Matt 21:23-41). At the close of His second parable, the Gospel of Matthew tells us, the Lord quoted the words to them which Peter now uses in their presence. 'Jesus says to them, Have ye never read in the Scriptures, The stone which they that builded rejected, has become the corner stone; this is the Lord and it is wonderful in our eyes? Therefore I say to you, that the kingdom of God shall be taken from you and shall be given to a nation producing the fruits of it. And he that falls on this stone shall be broke, but on whomsoever it shall fall it shall grind him to powder. And the chief priests and the Pharisees having heard His parables, knew that He spoke about them.' The One Hundred and Eighteenth Psalm from which the verse of the rejected stone is take, belongs to the hymn mention in Matt 26:30. It belongs to the Jewish ritual, known by the name of 'the great Hallel,' still used by the Jews during the Passover celebrations. But neither the modern nor the older Jewish expositors apply the words about the rejected stone to the Christ, their promised Messiah. Some say it refers to David himself, that he was the rejected stone and others apply it to the nation, rejected now but destined to be the corner stone of the nations. But the Lord had told them that He was the rejected stone mentioned in that Psalm, and here the Holy Spirit presses the same truth home to their hearts. They knew that the Lord meant them when He quoted that verse, that they were the builders, who were to reject. They had done so in fulfillment of that prophecy. Peter's words are directed straight at them, 'He is the stone which has been set at naught by you, the builders.'" (Gaebelein)
vss 8-12 - "In his answer, Peter actually puts his hearers on trial. He calls attention to the fact that the miracle was a good deed, not a crime (v 9) and that it was performed by the power of Jesus whom they had crucified (v 10). Jesus' rejection was predicted in the OT (v 11; Ps 118:22) and salvation is only through Him (v 12). All of this in 92 words in the Greek text!" (Ryrie)
by which we must be saved - "Peter says, 'whereby we [not 'ye'] must be saved.' While it is true that individual salvation is to be found in Christ alone, Peter here evidently refers to the salvation of the nation over which these men were the rules. Compare here Matt. 1:21 and Rom. 11:26." (Stam)
"It may seem at first sight that Peter is out of order speaking thus to God's appointed rulers, but we must not forget the words of our Lord to these same rules, as He warned them of the consequences of their rebellion: 'Therefore say I unto you, the kingdom of God shall be taken from you, and given to a nation bringing forth the fruits thereof' (Matt. 21:43). The 'nation' to whom the kingdom was to be given was the 'little flock' of His followers (Luke 12:32) and Peter and the eleven had already been appointed the supreme judges of that nation, to rule with Christ at His return: 'Matt. 19:28: 'And Jesus said unto them, Verily I say unto you, that ye which have followed Me, in the regeneration when the Son of man shall sit in the throne of His glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel.' Thus, while the apostles have been called to trial, in a deeper sense it is the rulers of Israel who are on trial for their rejection of Christ. Once more they are faced with the facts: You have slain your Messiah. Repent and receive Him now, or perish." (Stam)
***All this happened the day after Pentecost. A lot of action in a small amount of time.