“Neither Christ’s perfect humanity in His people nor Satan’s total depravity in His people are ever manifested totally in History.”
Dr. Gary North
Dominion & Common Grace — pg. 61
The antithesis remains real but the absolute fullness of it is only in principle. The fact that Christians still remain in need of much sanctification combined with the fact that pagans can not be perfectly wicked (apart from killing themselves) means that Christians and pagan interests can overlap to the degree that Christians are not yet perfectly sanctified and that pagans have not yet become perfectly conformed to their liege lord.
Now when an overlap of interests occur there will be vast tensions in the mutual agreement, for they are not in agreement in principle, but only in as much as they have not yet each worked out the implications of their Master’s wishes and nature. The agreement occurs in the context where the pagan is seeking (consciously or unconsciously) to build up his master’s Kingdom, while the Christian is seeking to build up his master’s kingdom.