Why do believers who have the Spirit groan inwardly?
Believers who have the firstfruits of the Spirit groan inwardly because they are waiting for the adoption, the redemption of the body. Their soul and spirit are already redeemed, but the corruptible body awaits its change into incorruptibility when they enter the Lord's presence, receive reward, and later participate in the kingdom.
Les explains that those who have the firstfruits of the Spirit groan within themselves while waiting for the adoption, that is, the redemption of the body. The redemption of the soul and spirit is already concluded, but the body is still corruptible. It will suddenly become incorruptible when believers go up into the Lord's presence, receive their reward, and later become active participants in the kingdom. This groaning also expresses longing for the Lord to come as the world moves toward the evil one, prompting the cry, "Lord, come quickly."