In Romans 8:16-18, Paul says, “The Spirit himself testifies with our spirit that we are God’s children. Now if we are children, then we are heirs—heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory. I consider that our present sufferings are not worth comparing with the glory that will be revealed in us.”
This seems to be a strange statement. It says it is those who share in Christ’s sufferings are the ones who are His heirs and will share His glory. Our suffering with Him and for Him is evidence that we belong to Him. It is this suffering, along with the Holy Spirit’s testimony with our spirits, that provides the assurance that we are His.
And again, we see that the price of the suffering is more than amply rewarded by the eternal results of that suffering. The temporary pain we experience pales in comparison to the glory we will receive for all eternity. This is indeed cause for great rejoicing.