Copied from: VoiceofJesus.org
If it is a lie, and you accuse me of lying, I will be forced to respond with a denial because a lie cannot and will not speak for itself. The things that motivated me to lie will motivate me to deny my lie. Then, feeling the weakness of my position, I look for something more! What more can I do? I must call forth a witness, so that you have not only my testimony, but also that of another. The scripture plainly states that everything is established at the mouth of two or three witnesses. You may have me pegged for a liar, but perhaps you will believe someone else. But on whom can I call on such short notice? To be effective, I must have a witness now! Not only so, but my witness must be a person of undisputed veracity, for it will not do to call on a reputed liar. Whose testimony would you accept immediately without question? Who? Who? Who?
Ah! There is only one person right for my task . . . God in heaven! His veracity is beyond question and He carries the extra advantage of never having been known to testify. He would surely condemn me for a liar if He were to testify but, since he never has, I am safe in calling upon him and the very mention of his name may be persuasive.
The God and Father of the Lord Jesus, he who is blessed forever, knows that I do not lie. At Damascus, the governor under King Aretas guarded the city of Damascus in order to seize me, but I was let down in a basket through a window in the wall, and escaped his hands (II Corinthians. 11:31-33).
But when he who had set me apart before I was born, and had called me through his grace, was pleased to reveal his Son to me, in order that I might preach him among the Gentiles, I did not confer with flesh and blood, nor did I go up to Jerusalem to those who were apostles before me, but I went away into Arabia; and again I returned to Damascus. Then after three years I went up to Jerusalem to visit Cephas, and remained with him fifteen days. But I saw none of the other apostles except James the Lord’s brother. In what I am writing to you, before God, I do not lie! (Galatians 1:15-20)
For this I was appointed a preacher and apostle (I am telling the truth, I am not lying), a teacher of the gentiles in faith and truth (I Timothy 2:7).
I am speaking the truth in Christ, I am not lying; my conscience bears witness in the Holy Spirit that I have great sorrow and unceasing anguish in my heart. For I could wish that I myself were accursed and cut off from Christ for the sake of my brethren, my kinsmen by race (Romans 9:1-3).
I count four times here, in the New Testament epistles, that Paul denied that he was lying: to the Corinthians, the Galatians, Timothy, and the Romans. Once, to the Romans, he called the Holy Spirit to witness for him. Twice, to the Corinthians and to the Galatians, he called God to witness for him. Three times, to the Corinthians, Galatians, and to Timothy, the denials were issued concerning his assertions of his calling and apostleship.