Unlike so many, we do not peddle the word of God for profit. On the contrary, in Christ we speak before God with sincerity, as those sent from God (2 Corinthians 2:17).
Paul preached the gospel for free, even though as an itinerant preacher he had the right to ask for support. So he writes in 1 Corinthians 9:14-18,
In the same way, the Lord has commanded that those who preach the gospel should receive their living from the gospel. But I have not used any of these rights. And I am not writing this in the hope that you will do such things for me, for I would rather die than allow anyone to deprive me of this boast. For when I preach the gospel, I cannot boast, since I am compelled to preach. Woe to me if I do not preach the gospel! If I preach voluntarily, I have a reward; if not voluntarily, I am simply discharging the trust committed to me. What then is my reward? Just this: that in preaching the gospel I may offer it free of charge, and so not make full use of my rights as a preacher of the gospel.
The Lord's command (1 Corinthians 9:14) is likely a reference to Jesus' sending out of the Twelve and the Seventy-two, where He commanded them not to take money belts but to live on the food, drink and shelter supplied to them by those to whom they preached. Paul, like those whom the Lord sent out, was also a traveling evangelist. As such, he had the right to this basic support. The rationale for this support may have been the difficulty for traveling evangelists to also work to support themselves. Nevertheless, Paul found a way and so was able to forgo the support he could have requested.
Thus, forgoing support, he had a powerful testimony to refute anyone accusing him of preaching for profit. He preached the Gospel free of charge. Even in Paul's day, many did just the opposite; namely, they materially profited from their preaching.
Paul gives an interesting explanation for his practice. He writes, "If I preach voluntarily, I have a reward; if not voluntarily, I am simply discharging the trust committed to me" (1 Corinthians 9:17). Consider this 1917 Swedish translation of this verse:
If this was my own enterprise, then I had a right to wages. But, since this is not my own enterprise, the mission that I have been entrusted with is only a stewardship given to a slave.
I like it because it brings out the meaning here. Paul is saying that his calling was not by choice but by obligation. He undertook the work not as a free man but as a slave, even a slave to God. And as a slave does not receive wages for their work, neither would he. Oh that more servants of the Gospel would have this same state of mind!