1 Corinthians 9:2-4

Amplified Bible

² If I am not [considered] an apostle to others, at least I am one to you; for you are the seal and the certificate and the living evidence of my apostleship in the Lord [confirming and authenticating it].

³ This is my defense to those who would put me on trial and interrogate me [concerning my authority as an apostle]: ⁴ Have we not the right to our food and drink [at the expense of the churches]?