Adam Clarke on 1 Corinthians 9:17

For if I do this thing willingly - If I be a cordial co-operator with God, I have a reward, an incorruptible crown, 1Cor 9:25. Or, if I freely preach this Gospel without being burthensome to any, I have a special reward; but if I do not, I have simply an office to fulfill, into which God has put me, and may fulfill it conscientiously, and claim my privileges at the same time; but then I lose that special reward which I have in view by preaching the Gospel without charge to any.

This and the 18th verse have been variously translated: Sir Norton Knatchbull and, after him, Mr. Wakefield translate the two passages thus: For if I do this willingly, I have a reward; but if I am intrusted with an office without my consent? what is my reward then? to make the Gospel of Christ, whilst I preach it, without charge, in not using to the utmost my privileges in the Gospel.

Others render the passage thus: But if I do it merely because I am obliged to it, I only discharge an office that is committed to me, 1Cor 9:18. For what then shall I be rewarded? It is for this, that, preaching the Gospel of Christ, I preach it freely, and do not insist on a claim which the Gospel itself gives me.