"Your sons and your daughters; and your young men... your elders" — this indicates that the Holy Spirit will pour out His gifts on everyone without distinction of sex and age. The expression "on My servants and on My handmaids" is significant in the original. In the Old Testament there was no case when slaves received the grace-filled gifts of the Holy Spirit and prophesied – in the New Testament the shackles of slavery will be broken, and the Holy Spirit will pour out His gifts on all, regardless of status, for in the Kingdom of Christ all are equal before the Lord – all are servants of the Lord.

With this prophecy of the abundant outpouring of the Holy Spirit is combined the prophecy of the judgment of the wicked world that will take place after this, and of the salvation of the true worshipers of the true God. The signs of the approach of this last Last Judgment of God over mankind are: "blood, and fire, and smoking smoke." These are symbols of bloodshed, indignation, war, and devastation. With this will be combined the signs in the heavens: the eclipse of the sun and the bloody appearance of the moon. All these horrors, in the figurative language of the sacred writers, denote in general all those great calamities in the human world, which will be the harbingers of God's judgment on the world. All this will happen "before the great and glorious day of the Lord comes." In the Old Testament, this "day" was understood as the "day of the Messiah", or in general the time of the Messiah, in the New Testament – the day of the Messiah's judgment over the world – the day of the Last Judgment.

However, he will be "saved" from judgment the one "who shall call upon the name of the Lord," of course, not only at this time and not only with his lips. "He will not simply call," explains St. John Chrysostom, "for not everyone," says Christ, "who says to Me, 'Lord, Lord, will enter the Kingdom of Heaven, but will call with diligence, with a good life, with due boldness.'" This refers to the righteous who truly believe in the Lord.

What did this prophecy have to do with the event of the day of Pentecost?

When the Apostle explained to his listeners that the miraculous event they had witnessed was the fulfillment of the Old Testament prophecy of Joel, this naturally gave rise to the thought that, consequently, the Messianic time had already come, the Messiah had already come. But where is He and Who is He? And so in his further speech the holy Apostle Peter begins his gospel about Christ. He announces to his listeners that the Messiah has appeared in the person of "Jesus of Nazareth, a man who has been testified to you by God by powers and wonders and signs..." The Apostle recalls the well-known miracles of Christ as proofs of His messianic dignity. However, for the Jews of that time, the cross suffered by Christ was a great temptation. In order to remove this temptation, St. Peter adds that the betrayal and mortification of Christ was accomplished: "according to the definite counsel and foreknowledge of God."

Removing the temptation that God could be crucified and die, the holy Apostle speaks of Christ, in relation to Jewish concepts, as a Man, the Son of David, and therefore expresses that "God raised Him," although Christ, as the Son of God, was resurrected by His own power and authority (cf. John 10:18) [10]. Speaking of the resurrection of the Lord, St. Peter cites the convincing testimony of King David from Psalm 15, verses 8-11. In this psalm, the Psalmist portrays a righteous man who speaks of his inner close communion with God and expresses joy that this communion will not be interrupted by death, that his soul will not remain in hell and his very body will not be subjected to corruption, but will enjoy the fullness of life in God and joy in communion with Him. The Apostle directly points out that David could not have said this about himself, since "he died and was buried" like an ordinary mortal man, but that it was David who spoke "about Him," i.e., about Christ. He said this, being a prophet in the narrow sense of the word, or a seer of the future, and knowing that God had promised him with an oath from the fruit of his loins to raise up Christ in the flesh and to seat him on his throne. This is indeed what we find in 2 Samuel 7:12-16 [11]. Then God gave David such a promise about the steadfastness of his house and about the eternity of his throne and kingdom, which could be fulfilled, of course, only in the Messiah, who was to descend according to the flesh from the line of David. David understood it that way at the same time, and glorified God with a song in verse 18-29. Psalm 131 speaks of the same prophecy of the Lord to David, that the Messiah will come from his lineage, and it is called an "oath": "The Lord swore to David the truth, and will not deny it" in the sense of the complete immutability of what was prophesied (Psalm 131:11).

"He first spoke of the resurrection of Christ," what David said in Psalm 15, verse 10, was fulfilled not in himself, but in his descendant in the flesh, Christ, for Christ, having died in the flesh, went down into hell with his soul, but did not remain there, but having preached to the spirits that were there about the redemption by His death of all mankind, He again gave life to His flesh, which had not seen corruption, and rose from the dead (see 1 Pet. 3:18-19) [12]. The truth of the resurrection of "this Jesus" is confirmed by St. Peter by the testimony of all believers: "of which we are all witnesses."

Further, St. Peter also testifies to the Ascension of Christ, the result of which was this outpouring of the grace of the Holy Spirit upon the faithful. Just as St. Peter affirmed the truth of Christ's resurrection on the prophecy of David, which was especially important for his Jewish listeners, so he affirms the truth of the Lord's Ascension by referring to verse 1 of the 109th Psalm. David, as we know, did not ascend to heaven himself, but says of his Lord that God seated him at His right hand: it is clear that David does not say this about himself, but about another person, namely, about the Messiah Jesus of Nazareth, Who ascended into heaven. The Lord Jesus Christ, during His earthly life, Himself added this prophecy to Himself (Matt. 22:42-45) [13], and St. Peter now applies it precisely to the ascension of the Lord and His sitting at the right hand of the Father.

In conclusion, the Apostle draws a practical conclusion from all that has been said: "Know therefore with certainty, all the house of Israel, that God has made this Jesus, Whom you have crucified, Lord and Christ" – the Jesus crucified by them is exactly the Messiah of whom the Old Testament prophets predicted.

"Whom ye have crucified" is a bold and powerful turn of phrase, with which the Apostle wanted to strike the hearts of his listeners as if with a sharp edge: God so exalted and magnified Him, and you crucified Him. "With this he beautifully concluded his word," says St. John Chrysostom, "in order to shake their souls."

The speech of the holy Apostle Peter did indeed have a powerful effect on his listeners. They were "pricked in heart," that is, they came to a state of contrition of heart, clearly imagining how grievously they had sinned before God and the Messiah. The inspired word of the Apostle, confirmed by the amazing event they had witnessed, strongly convinced them of the Messianic dignity of Jesus of Nazareth, and they turned to Peter and the other Apostles with a question full of reverence, love, and trust:

"What shall we do, men brethren?" that is, what shall we do in order to atone for our transgression, to receive the forgiveness of sins, and to enter into communion with the rejected Messiah?

St. Peter, on behalf of all the Apostles, points out the path of reconciliation with God not in any external deeds of Old Testament righteousness, but in repentance and baptism: "Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins; and receive the gift of the Holy Ghost." Here the Apostle demands of the Jews the same condition for entering the Kingdom of the Messiah, which was demanded earlier by St. John the Baptist and the Lord Jesus Christ when He began His preaching (see Matthew 3:2 [14] and 4:17 [15]). The first and most necessary condition for this is repentance, that is, the determination to radically change one's life, in particular for the Jews, the rejection of Judaism and conversion to Christianity. The second condition is baptism in the Name of Jesus Christ. These words do not contradict the commandment of the Lord Himself – to baptize "in the Name of the Father, and of the Son, and of the Holy Spirit": they denote only the main content of the faith and confession of those who are baptized – they must believe in Christ as the Messiah and with this faith approach baptism. For these two deeds, the Apostle promises them two saving consequences for them: the forgiveness of sins and the gift of the Holy Spirit. The salvation of man is accomplished in this twofold way: the laying aside of the old man with his sinful deeds and the putting on of the new one – the "new creation" of man by the power of the grace of the Holy Spirit.

"For the promise belongs unto you, and to your children, and to all that are far off, even as many as the Lord our God shall call" — the promise of God, given through the prophet Joel about the outpouring of the Holy Spirit, belongs first of all to the Jews, as the chosen people of God, and then to all the peoples of the earth, i.e. to the Gentiles, whom the Lord also calls into His Kingdom. St. Peter, however, speaks about this secretly, calling the pagans "distant," so that this thought would not seem tempting to the Jews, since they considered themselves worthy of the Kingdom of the Messiah.