If God says in Thessalonians that he’s going to call people to heaven, why does he say in Revelation that demons are going to kill a third of mankind?

Wow! Awesome question!

I started by finding the verses I think you were asking about. Here they are:

1 Thessalonians 4:16-17
16For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first. 17After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air. And so we will be with the Lord forever.

Revelation 9:14-19
14It said to the sixth angel who had the trumpet, "Release the four angels who are bound at the great river Euphrates." 15And the four angels who had been kept ready for this very hour and day and month and year were released to kill a third of mankind. 16The number of the mounted troops was two hundred million. I heard their number.
17The horses and riders I saw in my vision looked like this: Their breastplates were fiery red, dark blue, and yellow as sulfur. The heads of the horses resembled the heads of lions, and out of their mouths came fire, smoke and sulfur. 18A third of mankind was killed by the three plagues of fire, smoke and sulfur that came out of their mouths. 19The power of the horses was in their mouths and in their tails; for their tails were like snakes, having heads with which they inflict injury.

At first, this does seem a bit confusing, so let’s break this down and understand it. First, do you see that in Thessalonians God is calling people to heaven, but in Revelation it is again God who has sent the angels (even though they may be evil angels) to destroy a third of mankind?! Is that even more surprising, or what? (That’s important to understand, though … read on …)

In order to understand the Bible correctly, we have to understand that God gave these words to us and – because this is how awesome God is – one part of the Bible will agree with another part of the Bible. It becomes our job to understand it correctly! In order to do that, one of the things we have to understand is the “context” of the verses we are reading. Go grab a dictionary and look up the word, “context.” (go do that right now, and then finish reading this.)

So you see that “context” means the words, and sentences, and even the story that comes before and after the verse we are reading, AND (and this is very important) it affects the meaning and our understanding. If I tell you to go ahead and pick out a shirt to wear, but I don’t tell you whether we are going to a funeral or a football game, then you can easily pick out the wrong shirt (and obviously you would want a different shirt for those two times.) It would help if I gave you the “context” of why you needed to grab another shirt, right?

OK, back to Thessalonians and Revelation … what is the context of those verses? Take a few minutes right now to read the verses that come before and after the verses we are talking about (take a minute to do that right now …)

Here’s what’s going on with those two letters:

In 1 Thessalonians: the apostle Paul, Silas and Timothy have visited Thessalonica, a Greek city, on one of their missionary journeys. They started a church there, and many of the people who came to that church did not know God. The people there were enthusiastic about getting to know God, but they also had a lot of questions. And they didn’t always come up with the right answers!

Paul wrote back to that church (that’s the letter of 1 Thessalonians) to correct some of the errors they had made. One of the main issues he is writing about concerns what happens to people who believe in God when Jesus returns. You see, Paul was worried that the church there (because it was so young) would abandon their commitment to following Jesus, so Paul is writing to correct them and ALSO to encourage them!

SO – in 1 Thessalonians, the apostle Paul is encouraging new believers in Jesus Christ to hang in there even though things were at times a bit confusing and difficult.

Revelation was written by the apostle John at the very end of his life. John’s purpose was to comfort Christians who were going through really rough times; and Christians were being heavily attacked and persecuted during those days. John is telling his readers that the ultimate victory belongs to Jesus but – as you probably noticed – he uses some pretty wild and imaginative images to get his ideas across. He talks about horses of different colors and lakes of fire and swords coming out of mouths and WOW! how do we understand all that? Well, let’s remember that this letter is intended to comfort people (not to scare them, though the apostle John is not afraid to scare people into trusting Jesus!) and then recognize that this type of writing is called “apocalyptic.” (that’s a big word, but it just describes a kind of writing that uses lots of visions and wild images.) This is a little bit like how The Lord of the Rings or The Chronicles of Narnia stories are also pretty wild, but there are good stories and message there, right? Apocalyptic literature was a style of writing used to encourage people who were really being persecuted. Does that make sense to you?

In these verses in Revelation, Jesus is making it clear that those who don’t follow him (read verse 20 to see what all people were doing!) were going to be separated from him forever – and that sounds way harsh. But the context of this part of the story shows that ultimately God wins, Satan loses, and those who follow Jesus and accept him as their Savior, get to be with him forever. See, that’s the encouraging part that people needed to hear – and that’s the bigger picture that you and I have to understand. If we just see God as this God who is going to slay one third of mankind and we don’t realize that that third is the third that has rejected God, then we wonder if he is a mean God, or if we’re going to get killed like that.

SO – in Revelation, the apostle John is encouraging all believers in Jesus Christ to remain committed to him and to be comforted by the fact that in the end he wins, and Satan loses, even though things were way tough, confusing and difficult right then.