The Day of the Lord is near, when God will judge the whole earth.
15 Alas for that day! For the day of the LORD is near; it will come like destruction from the Almighty.
1 Blow the trumpet in Zion; sound the alarm on my holy hill. Let all who live in the land tremble, for the day of the LORD is coming. It is close at hand - 2 a day of darkness and gloom, a day of clouds and blackness. Like dawn spreading across the mountains a large and mighty army comes, such as never was of old nor ever will be in ages to come.
The day of the Lord is marked by the sign of the sun, moon and stars going black.
10 Before them the earth shakes, the sky trembles, the sun and moon are darkened, and the stars no longer shine. 11 The LORD thunders at the head of his army; his forces are beyond number, and mighty are those who obey his command. The day of the LORD is great; it is dreadful. Who can endure it? 12 'Even now,' declares the LORD, 'return to me with all your heart, with fasting and weeping and mourning.' 13 Rend your heart and not your garments. Return to the LORD your God, for he is gracious and compassionate, slow to anger and abounding in love, and he relents from sending calamity.
31 The sun will be turned to darkness and the moon to blood before the coming of the great and dreadful day of the LORD. 32 And everyone who calls on the name of the LORD will be saved; for on Mount Zion and in Jerusalem there will be deliverance, as the LORD has said, among the survivors whom the LORD calls.
13 Swing the sickle, for the harvest is ripe. Come, trample the grapes, for the winepress is full and the vats overflow -- so great is their wickedness!' 14 Multitudes, multitudes in the valley of decision! For the day of the LORD is near in the valley of decision. 15 The sun and moon will be darkened, and the stars no longer shine.
20 Will not the day of the LORD be darkness, not light -- pitch-dark, without a ray of brightness?
The day of the Lord will bring the return of Jesus Christ, who will judge the earth.
29 "Immediately after the distress of those days "'the sun will be darkened, and the moon will not give its light; the stars will fall from the sky, and the heavenly bodies will be shaken.' 30 "At that time the sign of the Son of Man will appear in the sky, and all the nations of the earth will mourn. They will see the Son of Man coming on the clouds of the sky, with power and great glory. 31 And he will send his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of the heavens to the other.
For those who are not redeemed through Jesus Christ, the day of the Lord will be a day of judgment.
14 "The great day of the LORD is near-- near and coming quickly. Listen! The cry on the day of the LORD will be bitter, the shouting of the warrior there. 15 That day will be a day of wrath, a day of distress and anguish, a day of trouble and ruin, a day of darkness and gloom, a day of clouds and blackness, 16 a day of trumpet and battle cry against the fortified cities and against the corner towers. 17 I will bring distress on the people and they will walk like blind men, because they have sinned against the LORD. Their blood will be poured out like dust and their entrails like filth. 18 Neither their silver nor their gold will be able to save them on the day of the LORD's wrath. In the fire of his jealousy the whole world will be consumed, for he will make a sudden end of all who live in the earth."
For those who are redeemed through Jesus Christ, the day of the Lord will be a day of salvation.
2 for you know very well that the day of the Lord will come like a thief in the night. 3 While people are saying, "Peace and safety," destruction will come on them suddenly, as labor pains on a pregnant woman, and they will not escape. 4 But you, brothers, are not in darkness so that this day should surprise you like a thief. 5 You are all sons of the light and sons of the day. We do not belong to the night or to the darkness. 6 So then, let us not be like others, who are asleep, but let us be alert and self-controlled.
2 Peter 3:10-14
10 But the day of the Lord will come like a thief. The heavens will disappear with a roar; the elements will be destroyed by fire, and the earth and everything in it will be laid bare. 11 Since everything will be destroyed in this way, what kind of people ought you to be? You ought to live holy and godly lives 12 as you look forward to the day of God and speed its coming. That day will bring about the destruction of the heavens by fire, and the elements will melt in the heat. 13 But in keeping with his promise we are looking forward to a new heaven and a new earth, the home of righteousness. 14 So then, dear friends, since you are looking forward to this, make every effort to be found spotless, blameless and at peace with him.