1 Corinthians 9 : 17 For if I do this thing willingly, I have a reward: but if against my will, a dispensation of the gospel is committed unto me. 18 What is my reward then? Verily that, when I preach the gospel, I may make the gospel of Christ without charge, that I abuse not my power in the gospel.

Paul here tells us that he is doing this willingly because he was chosen by God to to carry this message of Christ. He is not saying it was against his will but that God called him  and since it was  God’s choice and will for him he received not a reward but a stewardship. Since he followed the will God he will receive his reward in heaven. Paul is also saying his reward is being able to deliver the Gospel without having to receive anything from the ones he shared the Gospel with.  He had been given great power to deliver the Gospel but he refused to used that power to further himself. If we remember Paul was a tent maker and this helped to share the Gospel freely. We should learn from this that what God has given us to share we should be honored that He chosen us to help share the Gospel and do it knowing that we will receive the best reward when we are in heaven with Jesus.