When will the believer's corruptible body become incorruptible?
The believer's corruptible body becomes incorruptible at the redemption of the body, when believers go up into the presence of the Lord, receive their reward, and are made ready to come back as active participants in the kingdom. This awaits the Lord's coming, while the soul and spirit are already redeemed.
Les teaches that although believers have the firstfruits of the Spirit, they still groan inwardly, waiting for the adoption—the redemption of the body. The redemption of the soul and spirit is already concluded, but the body remains corruptible. Paul says in 1 Corinthians 15 that this corruptible body will suddenly become incorruptible when we go up into the Lord's presence, receive our reward, and prepare to return as active participants in the kingdom. Les also points to Colossians 1:12, where the Father has made us meet to be partakers of the inheritance, because believers are already members of the kingdom, which is now in heaven and will one day come to earth.