2 Corinthians 13:5; Examine Yourselves
2 Corinthians 13:5 Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates?
They themselves were the proof of his apostleship. It was through him that they were led to the Savior. If they wanted to see his credentials, they should look at themselves… But Paul is not telling the Corinthians to engage in self-examination as a proof of their salvation. Rather he is asking them to find in their salvation a proof of his apostleship. [MacDonald]
As for his faith in Christ, the Apostle Paul boldly declared in 2 Timothy 1:12 For the which cause I also suffer these things: nevertheless I am not ashamed: for I know whom I have believed, and am persuaded that he is able to keep that which I have committed unto him against that day.