Emotion of passion
“But I have made no use of any of these rights, nor am I writing this so that they may be applied in my case. Indeed, I would rather die than that—no one will deprive me of my ground for boasting!” 1 Corinthians 9.15
Metaphor
“If I am not an apostle to others, at least I am to you, for you are the seal of my apostleship in the Lord.” 1 Corinthians 9.2