Luke 21:25-27 "And there will be signs in the sun, in the moon, and in the stars; and on the earth distress of nations, with perplexity, the sea and the waves roaring; men's hearts failing them from fear and the expectation of those things which are coming on the earth, for the powers of heaven will be shaken. Then they will see the Son of Man coming in a cloud with power and great glory."
Because all men have heard the gospel so when they see the great earthquakes, blackening of the heaven, etc. they fear the coming judgment for their refusal to repent and accept Jesus as the Saviour.
Rev 6:15-17 And the kings of the earth, the great men, the rich men, the commanders, the mighty men, every slave and every free man, hid themselves in the caves and in the rocks of the mountains, and said to the mountains and rocks, "Fall on us and hide us from the face of Him who sits on the throne and from the wrath of the Lamb! "For the great day of His wrath has come, and who is able to stand?"
Sealing of the 144,000 Israelites
Rev 7:3-4 saying, "Do not harm the earth, the sea, or the trees till we have sealed the servants of our God on their foreheads." And I heard the number of those who were sealed. One hundred and forty-four thousand of all the tribes of the children of Israel were sealed:
After the elects are taken back to the throne of God at Rapture, the opening of the 7th Seal will bring in the wrath of the Lamb or God with the seven trumpets/bowls. Before then, all those 144,000 who believe and accept Jesus as their Messiah when they saw Him coming for His elects at Rapture will be sealed to protect them from the wrath just like in Egypt during the days of Moses when the Israelites were shielded from the wrath of God with 10 plagues upon Pharaoh and the Egyptians for not allowing the Israelites to go.
The Wrath of the Lamb or God
Rev 8:1-2, 7 When He opened the seventh seal, there was silence in heaven for about half an hour. And I saw the seven angels who stand before God, and to them were given seven trumpets.
This wrath is excruciating and many want death by they will not be able to find it. This is only a preview of the eternal suffering in the Lake of fire. This is definitely a warming that at all cost we must not be left behind at Rapture because of worldliness, covetousness, selfishness, unforgiveness and merciless towards our brethren.
Rev 9:4-6 They were commanded not to harm the grass of the earth, or any green thing, or any tree, but only those men who do not have the seal of God on their foreheads. And they were not given authority to kill them, but to torment them for five months. Their torment was like the torment of a scorpion when it strikes a man. In those days men will seek death and will not find it; they will desire to die, and death will flee from them.
The Two Witnesses
Rev 11:3, 7, 10 "And I will give power to my two witnesses, and they will prophesy one thousand two hundred and sixty days, clothed in sackcloth."... When they finish their testimony, the beast that ascends out of the bottomless pit will make war against them, overcome them, and kill them... And those who dwell on the earth will rejoice over them, make merry, and send gifts to one another, because these two prophets tormented those who dwell on the earth.
The two witnesses too will be around to call calamities from heaven to torment the people.
Brethren, at all cost ensure that all our families, friends, relatives and brethren are not left behind.