What does Acts 2:14-21 mean?

14 But Peter, standing up with the eleven, lifted up his voice, and said unto them, Ye men of Judaea, and all ye that dwell at Jerusalem, be this known unto you, and hearken to my words: 15 For these are not drunken, as ye suppose, seeing it is but the third hour of the day. 16 But this is that which was spoken by the prophet Joel; 17 And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: 18 And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy: 19 And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke: 20 The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come: 21 And it shall come to pass, that whosoever shall call on the name of the Lord shall be saved. (Acts 2:14-21 KJV)

William Burkitt’s Commentary

Observe here, The holy courage of St. Peter, in defending the innocency of the apostles, and confuting the calumny of drunkenness, which was now cast upon himself and them: These men are not drunken, as ye suppose, seeing it is but the third hour of the day.

Where note, 1. How he argues negatively from the time of the day: it was but the third hour of the day, that is nine o’clock in the morning, which was the hour for the morning sacrifice and prayer; and the worshippers of God (at the great feast especially) were never wont to eat or drink before those holy services were performed. In those times they went to their public devotions fasting; they served God before they served their bellies. The first fruits of the day were offered in the temple then; in the tavern now: ten in the morning and evening visits are made by some to the latter for one to the former.

Note farther, How he argues positively: he assures them, that the apostles were full of the Holy Ghost, and not full of wine; filled with the Spirit of God; and what was now done, was the completion of a prophecy uttered by Joel: That in the last days, that is, in the days of the Messias, there should be a most plentiful effusion of the Holy Spirit upon all flesh: that is, upon Jews and Gentiles, and upon all sorts of persons with out distinction, old and young, sons and daughters, bond and free.

Learn thence, That the Spirit of God is a free spirit, not confined to any party, to any order or degrees of men, but plentifully and abundantly poured forth under the gospel dispensation upon all believers. It is one of the great cheats which the pope has imposed upon the world, to persuade them to believe the Spirit of God is tied to the pommel of his chair; that he, and his cardinals, have monopolized the Holy Ghost. But, blessed be God, he has promised to pour out his Spirit upon all flesh, even upon servants and handmaids, to show, that he doth not despise persons of the lowest rank and condition in this world, but that the promise of the Spirit is made unto them also.

Observe lastly, What is here foretold that should come to pass after this great effusion of the Holy Spirit, namely, Wonder in the heaven, and signs in the earth, the sun turned into darkness, and the moon into blood. Which expressions signify the great miseries and troubles , the calamities and desolation, which should befall the Jews before the destruction of Jerusalem, for their crucifying the Lord of life and glory; unto which is subjoined the only way to escape and avoid them, namely, calling upon the Lord in fervent prayer and supplication: Whoever shall call upon the name of the Lord shall be saved. Intimating that prayer makes us shot-free, and is a sure defence in all storms, that no evil shall fatally touch our person, or come near our dwellings, whilst we take hold of God by faith, and approach unto him by prayer.

Lord! how happy is it when the strong afflictions from thee, raise strong affections in us towards thee!