Albert Barnes Commentary Joel 3:16

"And Jehovah will roar from Zion, and utter his voice from Jerusalem; and the heavens and the earth shall shake: but Jehovah will be a refuge unto his people, and a stronghold to the children of Israel." — Joel 3:16 (ASV)

The Lord shall roar out of Zion - As in the destruction of Sennacherib, when he was now close to his prey, and shook his hand against the mount of the daughter of Zion, the hill of Jerusalem, the Lord of hosts lopped the bough with terror, and the high ones of stature were hewn down, and the haughty were humbled (Isaiah 10:32–33), so it will be at the end.

It is foretold of antichrist that his destruction will be sudden: Then shall that Wicked one be revealed, whom the Lord shall consume with the spirit of His mouth, and shall destroy with the brightness of His Coming (2 Thessalonians 2:8). And Isaiah says of our Lord, He shall smite the earth with the rod of His mouth, and with the breath of His lips shall He slay the wicked (Isaiah 11:4). When the multitudes of God’s enemies are thronged together, then He will speak with His voice of terror. The terrible voice of God’s warnings is compared to the roaring of a lion: The lion hath roared, who will not fear? The Lord hath spoken, who can but prophesy? (Amos 3:8). Much more so, when those words of awe are fulfilled.

Our Lord then, The Lion of the tribe of Judah (Revelation 5:5), who is here called by the incommunicable Name of God, I am, will utter His awe-inspiring Voice, as it is said: The Lord Himself shall descend from heaven with a shout, with the voice of the Archangel and with the Trump of God (1 Thessalonians 4:16); and He Himself says, The hour is coming, in the which all that are in the graves shall hear His voice and shall come forth, they that have done good unto the Resurrection of life, and they that have done evil unto the resurrection of damnation (John 5:28–29).

And shall utter His voice from Jerusalem - This means either from His throne high in the air above the holy city, or from the heavenly Jerusalem, from the midst of the tens of thousands of His holy angels (Matthew 16:27; Matthew 25:31; Mark 8:38; 2 Thessalonians 1:7) and saints (Zechariah 14:5; Jude 1:14), who will come with Him.

So terrible will that voice be that the heavens and the earth shall shake. As it is said, the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up (2 Peter 3:10). And heaven shall open for the coming of the saints, and hell shall be moved at the coming (Isaiah 14:9) of the evil.

Nor will it be a slight shaking of the earth at His coming, but such that all the dead will be roused, as it were, from their sleep. Indeed, the very elect will fear and tremble; but, even in their fear and trembling, they will retain a strong hope.

This is what He says immediately: The Lord will be the hope (or place of refuge) of His people, and the strength (or stronghold) of the children of Israel—that is, of the true Israel, the whole people of the elect of God.

All these He will then, by His Majesty, at once wonderfully terrify and strengthen, because they always hoped in God, not in themselves, and always trusted in the strength of the Lord, never presumed on their own.

Conversely, the false Israelites hope in themselves, while, going about to establish their own righteousness, they submitted themselves not to the righteousness of God (Romans 10:3). The true Israel will trust much more than ever before; yet none can trust then who, in life, had not trusted in Him Alone.