Are carnal believers still co-laborers with God in His will?
Yes. Carnal believers can still be co-laborers in God's will. The Corinthians were carnal, divided, and not the most spiritual church, yet Paul still treated them as co-laborers with him. That same position applies to all believers, who labor together to bring the eternal will of God to fruition.
Les explains that Paul made it plain the Corinthians were still carnal. They were not a spiritual church like Ephesus or Philippi but were beset with all kinds of problems, especially divisions, with some claiming to follow Paul, Apollos, Peter, or even Christ. After addressing some of these issues and defending his apostleship, Paul comes to them in verse 9. Though they were carnal and not the most spiritual, Les points out they were nevertheless still co-laborers with the Apostle. That, Les says, puts us in the same place: we are co-laborers, all of us together, to bring to fruition the eternal will of God.
For we are labourers together with God: ye are God’s husbandry, ye are God’s building.
More Questions
What does it mean that we are laborers together with God?
Being 'laborers together with God' means the believer is hooked up with the Creator God Himself, which is far better than a wealthy person getting rich by being hooked up with another wealthy person.
Does it make a difference whether a carnal Christian or a spiritual giant does God's work?
As workers, every believer — whether carnal like the Corinthians or a spiritual giant like some great men of God — serves the same function, so that distinction makes no difference in the work.