What is the rapture of the church according to 1 Thessalonians 4?

According to 1 Thessalonians 4:17, the rapture of the church is the catching up of living believers together with other believers in the clouds to meet the Lord in the air. The pronouns 'we' and 'us' include Paul and believers, not unbelievers, and so they will ever be with the Lord.

Les explains that in 1 Thessalonians 4:17 Paul uses “we” and “us” to include himself with believers, never the unbeliever. This passage is commonly referred to as the rapture of the church: those who are alive and remain are caught up together with the other believers in the clouds to meet the Lord in the air, and so shall we ever be with the Lord. Then chapter 5 shows the other side of the coin: the unbelieving world, which will not be caught up to meet the Lord in the air. The day of the Lord comes as a thief in the night, when Christ will come in wrath and judgment.

1 Thessalonians 4:17

Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.

In 1 Thessalonians 4:17, who does 'we who are alive and remain' refer to?

The phrase refers to believers, the church, including the apostle Paul himself, not unbelievers. In the rapture of the church, they are the ones alive and remaining who will be caught up together with the other believers in the clouds to meet the Lord in the air.