The Bible is clear: the word "wrath" refers to God's judgment against sin upon the wicked and unbelieving.
Uses of the word "wrath"...
The word "wrath" is often used for final judgment on the unbelieving, God-rejecting, wicked. This finally occurs after the second coming of Christ.
Notice the two options: (1) salvation, vs (2) wrath.
This would not encourage the Thessalonians in the least unless they believed the rapture would happen in their lifetimes. But it didn't; why would Paul lie to them?
Christ's coming to redeem the faithful in his first coming is an act of judgment for the unbelieving wicked.
For of this you can be sure: No immoral, impure or greedy person — such a man is an idolater — has any inheritance in the kingdom of Christ and of God. Let no one deceive you with empty words, for because of such things God's wrath comes on those who are disobedient. (Ephesians 5:5-6)
Paul mentions the two final conclusions...
But your dead will live; their bodies will rise. You who dwell in the dust, wake up and shout for joy. Your dew is like the dew of the morning; the earth will give birth to her dead. Go, my people, enter your rooms and shut the doors behind you; hide yourselves for a little while until his wrath has passed by. (Isaiah 26:19-20)
The righteous will not be judged at the final judgment (God's "wrath") but the wicked will be judged.
The word "wrath" is often used for God's righteous judgment against a nation and/or individuals for wickedness. This includes judgment against the nation of Israel.
A few verses in which God pours out his wrath against his chosen nation Israel...
But the children rebelled against me: They did not follow my decrees, they were not careful to keep my laws — although the man who obeys them will live by them — and they desecrated my Sabbaths. So I said I would pour out my wrath on them and spend my anger against them in the desert. (Ezekiel 20:21)
In this verse God directs his wrath on a king of Israel.
Edom may say, "Though we have been crushed, we will rebuild the ruins". But this is what the LORD Almighty says: "They may build, but I will demolish. They will be called the Wicked Land, a people always under the wrath of the LORD". (Malachi 1:4)
In this verse God directs his wrath on Edom.
This prophecy refers to the overthrow of the Babylonian empire.
The king will do as he pleases. He will exalt and magnify himself above every god and will say unheard-of things against the God of gods. He will be successful until the time of wrath is completed, for what has been determined must take place. (Daniel 11:36)
The "king" is probably King Herod and the "Time of wrath" is probably the destruction of Jerusalem and the temple in the Jewish War of 67-70 A.D.
The word "wrath" can refer to the punishment on God's behalf by political rulers for rebelliousness against the state (the assumption being, the government is at least partially righteous).
Consequently, he who rebels against the authority is rebelling against what God has instituted, and those who do so will bring judgment on themselves. For rulers hold no terror for those who do right, but for those who do wrong. Do you want to be free from fear of the one in authority? Then do what is right and he will commend you. For he is God's servant to do you good. But if you do wrong, be afraid, for he does not bear the sword for nothing. He is God's servant, an agent of wrath to bring punishment on the wrongdoer. (Romans 13:2-4)
God uses the political rulers he has appointed to maintain order in society. We are to obey them as long as they don't demand that we disobey God.
God is in control of all things; even our trials and difficulties are examples of his wrath...