1 Corinthians 9:15

'But I have used none of these things, and I do not write these things that it may be so done in my case, for it were good for me rather to die, than that any man should make my glorifying void.'

But Paul himself has taken advantage of none of these things. Nor is he writing in order to do so. Indeed he would rather die than not to be able to say that he proclaims the Gospel freely and without charge. The last thing he wants is not to be able to glory in the successful preaching of the Gospel because by it he is seen as mercenary. He wants always to make it without hindrance (1 Corinthians 9:12) and without charge.