Therefore Paul ends 1 Corinthians chapter 9 by reminding his readers that our efforts for the Gospel are never in vain. If we discipline ourselves to pray, to mix with non-Christians and to share the Gospel with them no matter what their reaction may be, we will win a far greater prize than the laurel-crowned victors at the Isthmian games. Part of this prize will be simply to enjoy eternity with those we save from judgment. Another part will be that our efforts to spread the contagion of the Gosple provide powerful proof that we have truly believed it ourselves. Still more is the way our training prepares us to rule in the age to come and enables the Lord to entrust us with greater heavenly reward than we could ever have imagined.
From the book "Straight to the Heart of 1 & 2 Corinthians: 60 Bite-sized Insights (The Straight to the Heart Series)"