Paul's take on the end times

1 Thessalonians 4:13-18

Paul's concern here is that the Thessalonian church had some wrong beliefs about what would happen to those who were disciples of Christ but died before Christ's return. It is not indicated exactly what they believed but from the fact that they were grieving like everyone else, they probably believed that the dead ceased to exist and only those who were alive at Christ's return would live with him forever.
The key phrase in this passage is "according to the Lord's word." This means that Paul is taking his teaching on the return of Christ from Christ's teaching on his return. The place we find this teaching is in Matthew 24 and it is easy to see the parallels: there are clouds, there are angels and there are trumpets. Paul, through the inspiration of the Spirit, has passed on some further insight: the dead in Christ will rise first and we will go up to meet Jesus in the air, joining his army as he returns to take his rightful place as king.
The point of Paul's teaching isn't so much to explain everything that's going to happen when Jesus returns but to comfort and encourage the Thessalonians who believed that they would never see their dead relatives again (and that once they died, they would never see the fulfillment of the kingdom). The end of the paragraph is the key: encourage one another with these words. What an encouragement these words are: someday Jesus will return but if I should die before then, not even death can prevent me from seeing the fulfillment of Christ's kingdom. Lord, come!