2Co 13:3 Since ye seek a proof of Christ speaking in me, which to you-ward is not weak, but is mighty in you.
Because of the influence of false teachers, some in the church at Corinth were thinking that Paul was not an apostle sent from God. They were questioning him, accusing him of not being the real thing.
In today's world of Christianity we see many kinds of churches. Some are rich and prosperous and man centered. Much of what is taught in them is motivation for success, but not necessarily from God's word. Many have big names, and have a big following by teaching to itching ears, telling the people what they want to hear. There are some word churches that teach the word of God. They are cautious towards strange preachers, examining them by the word of God. This is as the church of Ephesus in Revelation. Jesus spoke to them that they had left their first love of him. They were swift to judge but slow to love others.
Rev 2:4 Nevertheless I have somewhat against thee, because thou hast left thy first love.
Paul goes on to say that the church should examine themselves before examining others.
2Co 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?
2Co 13:6 But I trust that ye shall know that we are not reprobates.
Paul was concerned for souls, not seeking personal glory. If Paul seemed to be as a reprobate to them, it is on Paul. They need to be sure about their own salvation.
2Co 13:7 Now I pray to God that ye do no evil; not that we should appear approved, but that ye should do that which is honest, though we be as reprobates.
2Co 13:8 For we can do nothing against the truth, but for the truth.
We can do nothing but the truth. The word of God is true and Jesus is the truth; the way, the truth and the life, so walk in the light of God's truth.
Rom 14:4 Who art thou that judgest another man's servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand.
There are some who make a ministry of finding fault with every preacher or teacher. My advise to them is to look twice at their own heart before making judgements of others. I was warned in a dream about being to quick to judge another person. We all have faults so we should seek to bring life and truth with love. Love is stronger than anything we can do or say, as in 1 Corinthians 13. We are to keep our eyes on Jesus, our first love.