Is the tribulation still future?
The tribulation remains ahead. In I Corinthians 15, a distinct company of people is contrasted with Israel, the Old Testament economy, and the tribulation that is still future. This confirms the tribulation has not yet occurred but is still ahead.
Les teaches through I Corinthians 15, the great resurrection chapter, and is building up to verse 23. He notes that the company of people being discussed is not Israel, is not out of the Old Testament economy, and is not in reference to that which is still ahead, the tribulation. Therefore, the tribulation is still future in the flow of Scripture he is explaining.